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Kibanya Muriithi studied Medical Laboratory Science at Masinde Muliro University of Science
and Technology. For Hematology, BTS, Clinical chemistry, Virology and immunology, you can
reach him through; (Phone no: 0740158079) (Email: kjmuriithi@gmail.com)

Any part of this book can be printed or reproduced for the purposes of knowledge
dissemination.

KMLTTB PRACTICAL
CLINICAL Chemistry

Slide 1

(a) Identify the colour of the urine shown in the spot

(b) Give the reason as to why urine take the colour you have named above

(c) Give 3 factors which may cause variations in urine output

(d) Name three parameters usually considered during physical examination of urine
Answers;

(a) Pale yellow or amber (1mrk)

(b) Due to the presence of various pigments collectively called urochrome. (1mrk)

(c) Fluid intake, diet, and climate. (1mrk)

(d) Odor colour, Specific gravity, Volume (1mrk)

Slide 2

(a) Identify the spot

(b) What are these these casts are composed of

(c) These casts are seen in conditions like?

Answers;

(a) White blood cell casts (1mrk)

(b) Renal epithelial cells. (1mrk)

(c) Renal tubular necrosis, viral disease (such as CMV nephritis), and kidney transplant (2mrks)

Slide 3

Identify the functional groups shown below

A. B
Answers;

Aldehyde functional group

Ketone functional group

Slide 4

(a) Identify the spot below

(b) State it's use

(c) State the principle of the instrument you have named in (a) above

Answers;

(a) Calorimeter (1mrk)

(b) Measures the absorbance of particular wavelengths of light by a specific solution. (2mrk)
(c) Determines the concentration of a known solute in a given solution by the application of
the Beer Lambert law, which states that the concentration of a solute is proportional to the
absorbance. (2mrk)

Slide 5

(a) Identify the spot

(b) Give a reason for your answer in (a) above

Answers;

(a) Oxalate crystals (1mrk)

(b) Look like little envelopes or tetrahedrons (1mrk)

Slide 6

(a) Describe the Benzidine test for detection of blood in urine

(b) Give any other chemical test for detection of blood in urine

(c) Give one advantage of this test you have named in (b) above

Answers;

(a) Make saturated solution of benzidine in glacial acetic acid. Mix 1 ml of this solution with 1
ml of hydrogen peroxide in a test tube. Add 2 ml of urine. If green or blue color develops
within 5 minutes, the test is positive. (4mrks)

(b) Orthotoluidine test: In this test, instead of benzidine, orthotoluidine is used. (2mrk)

(c) It is more sensitive than benzidine test. (1mrk)

Slide 7

A patient presented with urine producing an odor similar to that usually produced by the
organisms shown on the right

(a) Identify the odor and state what it may suggest

(b) Name two other typical odors in urine and what they may suggest

(c) Name the organic constituents of normal urine

(d) Name the abnormal urine constituents

Answers;

(a) Fishy odor, suggesting urinary tract infection with Proteus.(1mrk)

(b) Fruity, suggesting Ketoacidosis or starvation, Ammoniacal suggesting urinary tract

infection with Escherichia coli or old standing urine. (4mrks)
(c) Urea, uric acid, creatinine (2mrks)

(d) Proteins, glucose, bile pigments, blood, ketone bodies (2mrks)

Slide 8

(a) Identify the spot

(b) Give a reason for your answer in (a) above

Answers;

(a) Cystine crystals (1mrk)

(b) Shaped like stop signs (1mrk)

Slide 9

(a) Identify the spot below

(b) Give it's application

(c) Give three daily care and maintenance practices for the spot above

Answers;

(a) Flame Photometer (1mrk)

(b) Commonly used for the quantitative measurement of sodium and potassium in body
fluids. (1mrk)

(c) Empty waste container, if used., Check air line for condensation, and drain if necessary.,
Check whether the ‘U’ tube is filled with deionised water. (3mrks)
Slide 10

(a) Identify the spots below

(b) State their functions

Answers;

(a) Manual pipettes (1mrk)

(b) Used for accurate volumetric measurements and transfers. (1mrk)

Slide 11

(a) Identify the spot

(b) Give three care and maintenance practices for the spot above

Answers;

(a) Analytical balance (1mrk)

(b) Choose a balance appropriate for the range of the object to be weighed and the precision
of a particular analysis, Prior to use, the balance should be checked for spilled substances and
spilled solids should be brushed away, Ensure that the balance is leveled, on a stable surface,
Place the balance away from air currents. (Any 3) (3mrks)
Slide 12

(a) Identify the spot below

(b) State it's use

(c) Give three necessary care and maintenance practices of the spot above

Answers;

(a) An autoclave (1mrk)

(b) used mainly for sterilization of dirty glassware, instruments and material to be discarded.
(1mrk)
(c) Check temperature daily, Clean cool chamber and defrost the evaporator monthly, Clean
refrigerator from the outside. (1mrk)

Slide 13

The slide on the right was made using the contents present in the container shown below

(a) Identify the most probable sample present in the container

(b) Name 3 categories of defects that can be seen during microscopic examination of the
sample.

(c) What is Azoospermia?

(d) What is Aspermia?

(e) Name three glands which usually contribute to the final composition of the sample
present in container
Answers;

(a) Semen (1mrk)

(b) Head shape/size defects, including large, small, tapering, pyriform, amorphous,
vacuolated or double heads, or any combination of thes, Neck and midpiece defects,
including absent tail, non inserted or bent tail, Tail defects, including short, multiple, hairpin,
broken, irregular width, or coiled tails, tails with terminal droplets, or any combination of
these, Cytoplasmic droplets greater than one-third of the area of a normal sperm head.
(4mrks)

(c) Lack of sperm in the ejaculate (1mrk)

(d) Lack of ejaculate (1mrk)

(e) Testis, prostate glands, seminal vesicles, and bulbourethral glands. (Any 3) (3mrks)

Slide 14

Identify the spot

Answers;

Drug testing kit (1mrk)

Slide 15

(a) Identify the spot below

(b) State the principle of the instrument you have named in (a) above
Answers;

(a) Ph metre (1mrk)

(b) The pH measurement is based on the physical principle that an electric potential will be
established on the surface of a metal (electrode) placed into a dilute salt solution. (2mrks)
Slide 16

(a) Identify the method of urine preservation shown below

(b) The process should be done at a temperature of how many degrees Celsius

(c) Describe four other methods of urine preservation

Answers;

(a) Refrigeration (1mrk)

(b) 4-6°C (1mrk)

(c) Hydrochloric acid: It is used for preservation of a 24- hour urine sample for adrenaline,
noradrenaline, vanillylmandelic acid, and steroids.

Toluene: It forms a thin layer over the surface and acts as a physical barrier for bacteria and
air. It is used for measurement of chemicals.

Boric acid: A general preservative.

Thymol: It inhibits bacteria and fungi.

Formalin: It is an excellent chemical for preservation of formed elements. (8mrks)

Slide 17

(a) Identify the spot

(b) What does the appearance of the spot identified in (a) above in urine suggest

(c) Name two chemical tests for significant bacteriuria

(d) Give two examples of bacteria which can produce a positive nitrite test

(e) What is usually detected in the leucocyte esterase test?

Answers;

(a) Renal tubular cell cast (1mrk)

(b) Injury to the tubular epithelium (1mrk)

(c) Leucocyte esterase test, Nitrite test: (2mrks)

(d) E.coli,Salmonella, Proteus, Klebsiella, (2mrks)

(e) It detects esterase enzyme released in urine from granules of leucocytes. (1mrk)
Slide 18

(a) Identify the spot below

(b) Give any 3 uses of the spot you have named in (a) above

Answers;

(a) Fluorometer (1mrk)

(b) To quantify amino acids and peptides by labelling with an extrinsic fluor acridine orange,
In cell sorting and cell counting, To detect malignant cells, To quantify catecholamine,
quinidine and porphyrin, For localization of enzymes in cells and metals in metalloproteins.
Any 3 (3mrk)

Slide 19

(a) What does foamy urine suggest according to you?

(b) What is anuria

(c) Give five changes that occur when urine is left standing for a long time at room
temperature.

(d) Within a maximum of how many hours must urine samples must be tested in the
laboratory so as to get the correct results?

Answers;

(a) Presence of excess proteins or bilirubin. (1mrk)

(b) Complete cessation of urine output (1mrk)

(c) Increase in pH due to production of ammonia from urea by urease-producing bacteria.

Formation of crystals due to precipitation of phosphates and calcium (making the urine
turbid). Loss of ketone bodies, since they are volatile. Decrease in glucose due to glycolysis
and utilization of glucose by cells and bacteria. Oxidation of bilirubin to biliverdin causing
false- negative test for bilirubin. Oxidation of urobilinogen to urobilin causing false- negative
test for urobilinogen. Bacterial proliferation Disintegration of cellular elements, especially in
alkaline and hypotonic urine. Any 5 (5mrks)

(d) Within 2 hours of collection (1mrk)

Slide 20

(a) Identify the spot

(b) The presence of red blood cells within the cast is always pathologic, and usually strongly
indicative of?
(c) Give two conditions in which you are likely to see waxy casts

Answers;

(a) Red blood cell casts (1mrk

(b) Glomerular damage. (1mrk)

(c) Severe chronic renal disease and renal amyloidosis. (2mrks

Slide 21

(a) Identify the spots

(b) Briefly describe three methods of urine collection

(a) Urine test strips (1mrk)

(b) Random collection taken at any time of day with no precautions regarding contamination.

Early morning collection of the sample before ingestion of any fluid.

Clean-catch, midstream urine specimen collected after cleansing the external urethral meatus.

Catherization of the bladder through the urethra for urine collection is carried out only in
special circumstances, i.e., in a comatose or confused patient.

Suprapubic transabdominal needle aspiration of the bladder. When done under ideal
conditions, this provides the purest sampling of bladder urine. This is a good method for
infants and small children. (Any 3) (6mrks)
Slide 22

(a) Identify the instrument inside the jar shown below

(b) What is it usually used for

(c) What is urine specific gravity

(d) What is it used for in urinalysis

(e) What is the normal SG of urine?

(f) Name four possible causes of an increased SG of urine.

(g) Name four possible causes of a decrease SG of urine

Answers;

(a) Urinometer (1mrk)

(b) To measure urine specific gravity (1mrk)

(c) Is a comparison of density of urine against the density of distilled water at a particular
temperature. (1mrk)

(d)To measure of concentrating ability of kidneys and is determined to get information about
this tubular function. (1mrk)
(e) 1.016 to 1.022 (1mrk)

(f) Diabetes mellitus, Albuminuria, Fever, Dehydration. (1mrk)

(g) Diabetes insipidus, Pyelonephritis, Diuretics (1mrk)

Slide 23

(a) Identify the spot

(b) Give a reason for your answer in (a) above

Answers;

(a) Broad waxy cast (1mrk)

(b) Sharp edges and the presence of cracks (1mrk)

Slide 24

(a) Identify the spot below

(b) Give any 3 parts of the spot you have named in (a) above

(c) Briefly describe how the spot works

(d) Give three necessary care and maintenance practices of the spot above

Answers;

(a) spectrophotometer (1mrk)

(b) Lamp, Prism, Sample holder, Photomultiplier, Display ,(3mrks)

(c) White light hits grating or prism, Light is split into colours of the rainbow, Wavelength
knob directs different colours towards sample. (2mrk)
(d) Set the instrument up on a level bench where it will be free from vibrations and not in
direct sunlight, Instrument should be protected from dust with a cover, Manufacturer’s
instructions should be adhered during installation, operation and maintenance., Standard
operating procedures should be prepared including the use cuvettes, operation of the
instrument and waste disposal. (Any 3) (4mrks)

Slide 25

Identify the test shown below for detecting the presence of proteins in urine

(a) Give the principle of the test you have named in a above

(b) Give the interpretation of the test

(c) Name four substances in urine which can be examined chemically

Answers;

(a) Heat and acetic acid test (1mrk)

(b) Proteins are denatured & coagulated upon heating to give white cloud precipitate (1mrk)

(c) If turbidity or precipitation disappears on addition of acetic acid after heating, it is due to
phosphates. if turbidity or precipitation persists after addition of acetic acid, then it is due to
proteins. (1mrk)

(d) Proteins, Glucose, Ketones, Bilirubin, Bile salts, Urobilinogen, Blood, Hemoglobin,
leukocyte esterase (1mrk)

Slide 26

(a) State what the appearance of a pink colour on the spot shown below might indicate

Answers;

(a) Might indicate bacterial infection with gram- negative rods (like E. coli) (1mrk)
Slide 26

(a) Identify the spot below

(b) State the principle of the sulphosalicylic acid Test for proteins in urine.
(c)Give three indications for urinalysis

Answers;

(a) Sulphosalicylic acid (1mrk)

(b) Addition of sulphosalicylic acid to the urine causes formation of a white precipitate if
proteins are present. Method – Turbidity persists after heating indicating the presence of
proteins (2mrks)

(c) Suspected renal diseases like nephrotic syndrome, Detection of urinary tract infection,
Detection and management of metabolic disorders like diabetes mellitus, Differential
diagnosis of jaundice, Diagnosis of pregnancy. Any 3 (3mrks)

Slide 27

Identify the test shown below

(b) Describe the principle of the reagent Strip test for proteins

(c) Reagent strip test is mainly reactive to which protein fraction?

(d) State one disadvantage of the reagent strip test for proteins

(e) Give two conditions which can lead to excess production of Bence Jones proteins

Answers;

(a) Heat coagulation test for proteins (1mrk)

(b) The reagent area of the strip is coated with bromophenol blue indicator and buffered to
an acid pH which changes color in the presence of proteins(3mrks)

(c) Albumin. (1mrk)

(d) It is false-negative in the presence of Bence Jones proteins and myoglobin (2mrk)

(e) Multiple myeloma, Primary amyloidosis. (1mrk)

Slide 28

(a) Identify the spot

(b) Give a reason for your answer in (a) above

Answers;

(a) Triple phosphate crystals (1mrk)

(b) Look like rectangles (1mrk)

Slide 29

(a) Identify the spot below

(b) Give three necessary care and maintenance practices of the spot above

(a) Water bath (1mrk)

(b) The level of water in the water bath should be above the level of the solution in tubes to
be incubated, Temperature should be maintained daily, Prior to incubating the tubes, check
the temperature at the centre and four corners of the water bath. When incubating open
containers, vials or tubes the water bath lid should be removed to prevent contamination and
dilution of the incubated material by condensed water. The water bath must be refilled to
prevent growth of algae and bacteria. The heating element should always be kept clean.
(Any 3) (3mrks)
Slide 30

(a) Identify the name of the process undergone by a urine sample whose results of the
procedure are shown below

(b) What is protein electrophoresis

(c) Apart from the test whose results are shown above briefly describe any other test for
Bence Jones Proteinuria

Answers;

(a) Protein electrophoresis (1mrk)

(b) Movement of charged particles through an electrolyte subjected to an electric field (2mrks)

(c) Bence Jones proteins precipitate at temperatures between 40-60°C. (other proteins
precipitate between 60-70°C) The precipitate disappears on further heating at 85-100°C.
(while precipitate of other proteins does not) When cooled (60-85°C), (3mrks)
Slide 31

(a) Identify the spot shown below

(b) Give two main indications for testing glucose in urine is

(c) Give three possible causes of glycosuria with hyperglycemia

Answers;

(a) Glucometre (1mrk)

(b) Detection of unsuspected diabetes mellitus or follow-up of known diabetic patients. (1mrk)

(c) Diabetes mellitus, Cushing’s syndrome, hyperthyroidism, pancreatic disease. (3mrks)

Slide 32

(a) Give the most probable identity of the casts shown below

(b) Give a reason for your answer in a above

(c) Explain how the presence of these casts come about

(d) State two clinical conditions in which it is possible to see the casts you have named above

Answers;

(a) Granular casts (1mrk)

(b) They have a textured appearance which ranges from fine to coarse in character. (1mrk)

(c) Result either from the degeneration of cellular casts, or direct aggregation of plasma
proteins or immunoglobulin light chains. (1mrk)

(d) Chronic renal diseases, acute tubular necrosis etc. (1mrk)

Slide 33

(a) Give two possible Causes of Ketonuria

Answers;

(a) Decreased availability of carbohydrates in the diet in Starvation, Persistent vomiting in

children, Weight reduction programs.

Increased metabolic needs eg in, Fever in children, Severe thyrotoxicosis, Pregnancy, Protein
calorie malnutrition (4mrks)

Slide 34
(a) State one Solution you can utilize in the lab to test for the presence of the compound
shown below in urine

(b) What is the name of the test that utilizes the solution you have named above?

(c) Briefly describe the principle of the test you have named in (b) above

(d) Give one disadvantage of the above test whose principle you have just described

Answers;

(a) Ferric chloride solution (1mrk)

(b) Ferric chloride test (Gerhardt’s) (1mrk)

(c) Addition of 10% ferric chloride solution to urine causes solution to become reddish or
purplish if acetoacetic acid is present. (1mrk)

(d) The test is not specific since certain drugs (salicylate and L-dopa)give similar reaction.
(1mrk)
Slide 35

(a) Identify the spot below

(b) State it's use

Answers;

(a) Hot air oven (1mrk)

(b) Used mainly for drying laboratory equipment in dry air, Some hot ovens are used for
sterilization. (1mrk)
Slide 36

(a) Identify the colour of the urine shown below

(b) What name do we give to the presence of blood urine

(c) Name four factors that can cause blood in urine

(d) Give the name of the drug commonly implicated in hematuria

Answers;

(a) Red (1mrk)

(b) Hematuria (1mrk)

(c) Urinary tract infections, an enlarged prostate, cancerous and noncancerous tumors,
kidney cysts, long-distance running, and kidney or bladder stones. (2mrks)

(d) Rifampicin (Rifadin, Rimactane), an antibiotic often used to treat tuberculosis. (1mrk)
Slide 37

(a) Where in the body is urobilinogen produced

(b) From what raw material is urobilinogen produced

(c) What would complete absence of urobilinogen in urine suggest

(d) What would a significant increase in the urobilinogen levels suggest

Answers;

(a) Intestines (1mrk)

(b) Bilirubin (1mrk)

(c) disease or biliary obstruction (1mrk)

(d) Hepatitis, cirrhosis, biliary disease (1mrk)

Slide 38

(a) Give the most probable identity of the casts shown below

(b) State the Identification features

(c) What are they composed of?

(d) Give examples of conditions in which they can be seen

(e) Give two examples of crystals that can be found in acidic urine

(f) Give two examples of crystals that can be found in alkaline urine

(g) Casts are of two main types, name the two types and give an example of each

Answers;

(a) Hyaline casts (1mrk)

(b) Appear very pale and slightly retractile (1mrk)

(c) Solidified Tamm-Horsfall mucoprotein. (1mrk)

(d) They may be seen in healthy patients, increased numbers during dehydration, exercise or
diuretic medicines. (1mrk)

(e) Uric acid, Calcium oxalate, Cystine, Leucine Crystals. (1mrk)

(f) Ammonium magnesium phosphates(triple phosphate crystals), Calcium carbonate,
Amorphous phosphates, Ammonium urate crystals. (2mrks)

(g) Noncellular: Hyaline, granular, waxy, fatty

Cellular: Red blood cell, white blood cell, renal tubular epithelial cell. (2mrks)

Slide 39

(a) What would the appearance of Bilirubin +++ on the spot shown below suggest to you

(b) What is bilirubinuria

(c) What happens when a urine sample with high bilirubin levels is shaken

Answers;

(a) Presence of liver disease or biliary obstruction (1mrk)

(b) Appearance of bilirubin in urine (1mrk)

(c) Yellow foam is formed (1mrk)

Slide 40

(a) Identify the spot

(b) Give a reason for your answer in (a) above

(c) Explain what has happened to the RBC pointed by the arrow

(d) What is hematuria

(e) Give examples of conditions in which hematuria can be seen

Answers;

(a) Red blood cells (1mrk)

(b) Appear as refractile disks (1mrk)

(c) With hypertonicity they have acquired a crenated appearance (1mrk)

(d) Presence of blood in urine (1mrk)

(e) Sickle cell anemia, incompatible blood transfusion, snake bites, coagulation abnormalities
(2mrks)

Slide 41

(a) Which test for carbohydrates is likely to give the results shown below

(b) Why is the test you have named above important in carbohydrates testing

Answers;

(a) Seliwanoffs test (1mrk)

(b) It helps distinguish between hexoses with a ketone group and hexoses that are aldehydes.
(2mrks)
Slide 42

(a) Identify the spot

(b) Name the constituents of the spot identified in (a) above

(c) Give one possible cause of glycosuria without hyperglycemia:

(d) State the principle of the test that utilizes the spot above

Answers;

(a) Benedict's reagent. (1mrk)

(b) Copper sulphate, sodium citrate, sodium carbonate (2mrks)

(c) Renal glycosuria, the disorder is transmitted as autosomal dominant (1mrk)

(d) When urine is boiled in Benedict’s qualitative solution, blue alkaline copper sulphate is
reduced to red-brown cuprous oxide if abreducing agent is present (3mrks)

Slide 43

(a) Suggest a possible reason why urine can have a pH of 5 on the spot below

(b) Suggest a possible reason why urine can have a pH of 9 on the spot below

(c) Phosphates will precipitate in

(c) Uric acid will precipitate in

Answers;
(a) High protein diet, Ketoacidosis (1mrk)

(b) Vegetarian diet, UTI (1mrk)

(c) Alkaline urine (1mrk)

(d) Acidic urine (1mrk)

Slide 44

(a) Identify the spot

(b) Give three necessary care and maintenance practices of the spot above

Answers;

(a) Centrifuge (1mrk)

(b) Always follow the manufacturer’s instructions for installation, operation, cleaning,
maintenance, lubrication, repair and replacement, The instrument must be positioned exactly
horizontally to prevent the instrument moving away from its place during centrifugation,
Check if the rubber buffers/cushions are in the buckets, Always balance the tubes and
buckets in the centrifuge, Turn the speed control slowly to the required speed, Do not use the
centrifuge at a higher speed than necessary. (Any 3) (3mrks)

Slide 45

(a) What would the appearance of Leucocytes ++ on the spot below indicate?
(b) What is Pyuria

(c) What is Cystitis

(d) What is pyelonephritis

Answers;

(a) Infection or inflammation (1mrk)

(b) Leukocytes in urine (1mrk)

(c) Bladder infection (1mrk)

(d) Kidney infection (1mrk)

Slide

(a) Identify the spot

(b) Give a reason for your answer in (a) above

Answers;

(a) White blood cells (1mrk)

(b) Lobed nuclei, Refractile cytoplasmic granules. (1mrk)

Slide 46

(a) Identify the test shown below

(b) What is the significance of the named above

(c) How will the reaction between monosaccharides and disaccharides differ

(d) How will the test result be in the presence of monosaccharides

Answers;

(a) Barfoed's test (1mrk)

(b) Used to distinguish between disaccharides and monosaccharides (1mrk)

(c) Monosaccharides reacts very fast whereas the reaction with disaccharides is slow. (2mrks)

(d) There will be formation of a brick red precipitate (1mrk)

Histology

Slide 1

(a) Identify the spots

(b) Briefly describe how the resins may be regenerated after use

(c) Give two advantages of their use in decalcification

(d) Give three qualities of a good decalcification process.

Answers;

(a) Ion exchange resins (1mrk)

(b) May be regenerated with dilute N/10 HCL followed by distilled water (1mrk)

(c) Tissue preservation, Cellular details better preserved. (2mrks)

(d) There is complete removal of Calcium ions, There is no distortion of tissue structures and
cells, There are no harmful effects on subsequent staining results. (3mrks)
Slide 2

(a) Identify the spot

(b) state the application of the spots you have named in (a)

above

Answers;

(a) Tissue cassettes (1mrk)

(b) Used to hold samples of all sizes for histological processing (1mrk)
Slide 3

Differentiate between the spots

A. B.

Answers;

A Untrimmed tissue block (1mrk)

B Trimmed tissue block with excess paraffin removed and block face in a trapezoid shape. (1mrk)
Slide 4

(a) Identify the procedure shown below

(b) Briefly describe the steps usually followed for the procedure you have named in (a) above

Answers;

(a) Embedding (1mrk)

(b) Place tissue cassette in melted parafin, Fill mold with paraffin, Place tissue in mold, Allow
to cool (2mrks)
Slide 5

Describe the end point of decalcification test that utilizes the spots shown below

Answers;

Relies on the detection of dissolved calcium in the decalcifying solution when no further
calcium is detected decalcification is complete.

Consist of two stages- positive result at either stage indicates that further decalcification of
the tissue in fresh fluid.
Decant 5ml of the used decalcifying fluid into a clean test tube
Add a small piece of litmus
Add strong ammonia drop by drop whilst agitating the tube until the litmus paper turns blue
indicating alkalinity

If the solution becomes turbid at this stage due to formation of calcium hydroxide, then
decalcification is incomplete –not necessary to proceed further
If the solution remains clear, proceed with the second stage of test

Add 0.5 mls saturated aqueous ammonium oxalate stand 30mins

If turbidity occur due to formation of calcium oxalate then decalcification is incomplete-tissue

requires further decalcification
If solution remains clear decalcification is complete

(20mrks)

Slide 6

(a) Identify the spot shown below

(b) Advantage of using this method over the manual processing

(c) What is tissue processing

(d) Give five factors that usually have an effect on tissue processing
Answers;

(a) Automatic tissue processer (1mrk)

(b) Reduces time taken for processing, Superior results are obtained, Multiple blocks can be
processed together, Less laborious (3mrks)

(c) Tixsue processing is the treatment of tissue with various reagents to enable production of
thin sections for microscopic examination. (1mrk)

(d) Size of the tissue, Penetrability of tissue (Density), Viscosity of reagents, Temperature,
Agitation, Vacuum. (3mrks)

Slide 7

(a) Identify the spot shown below

(b) What is embedding

(c) Give any other name usually given to embedding

Answers;

(a) Embedded tissue block (1mrk)

(b) It is a stage whereby tissue is supported by paraffin wax or any other medium by being
made into a block ready for section cutting (1mrk)

(c) Blocking out or casting. (1mrk)

Slide 8

(a) Identify the following embedding tools

(b) What is embedding

Answers;

(a) Moulds (1mrk)

(b) The process by which impregnated tissues are sorrounded by a medium such as agar,
gelatin or wax which when solidified will provide sufficient external support during sectioning.
(3mrks)

Slide 9

(a) Identify the spot shown below

(b) Name three other substances which can be used instead of the spot shown below

(c) What is Impregnation?

(d) What is the importance of impregnation

Answers;

(a) Paraffin wax (1mrk)

(b) Candle wax, Ester wax, Carbowax (polyethylene glycol), paraplast, Water soluble waxes,
Gelatine, Agar, Low viscosity nitrocellulose (LVN) and Celloidin. Any 3 (3mrks)

(c) Saturation of the tissue with the infiltration medium. (1mrk)

(d) It is done to remove the clearing agent and air form tissues and also to allow the
impregnating media penetrate into the tissue so that a block is produced while be cut into
sections (slices). (2mrks)
Slide 10

(a) Identify the spot shown below

(b) State it's use

Answers;

(a) Biopsy sponge pads (1mrk)

(b) Used to hold biopsies in place and prevent them from being lost during processing (1mrk)

Slide 11

(a) Identify the spot shown below

(b) State it's use

Answers;

(a) Cassette baskets (1mrk)

(b) suitable for holding and identifying tissue samples in processing, embedding, and
sectioning procedures. (1mrk)
Slide 12

(a) Identify the spot shown below

Answers;

(a) Forceps (1mrk)

Slide 13

(a) Identify the spots below

(b) State the Principle of the staining method that utilizes the above stains

(c) Give the Expected results that can be obtained from a tissue stained with H&E

Answers;

(a) Hematoxylin and Eosin stains (1mrk)

(b) Haematoxylin stain is a basic stain and it stains the nuclear because it is acidic while eosin
being an acid stain is taken up by the basic tissue structure like the cytoplasm. (3mrks)

(c) Nuclei – blue – Purple

Cytoplasm – Red to pink

Red blood cells- Orange

Rest of tissue – shades of red pink (3mrks)

Slide 14

(a) Identify the spot shown below

(b) State it's use

Answers;

(a) Hot stir plate (1mrk)

(b) keeps liquids circulating as they are heated for a faster, more even reaction. (1mrk)

Slide 15

(a) Identify the spot shown below

(b) State it's use

Answers;

(a) Wax dispenser (1mrk)

(b) A Paraffin or Wax dispenser melts the solid paraffin, maintains it in its molten form and
can dispense it as and when required. (1mrk)
Slide 16

(a) Identify the spot shown below

(b) State 5 care and maintenance practices for microtome knives

Answers;

(a) Microtome knife (1mrk)

(b) Knives should be stored in their boxes when not in use

Knives should never be laid flat on the bench

Never allow edge of knife to be badly kicked

Knife edge should be touched up (sharpen ) daily before use

Always use a knife back. When sharpening Plano concave and plane wedge knife

Knives should be cleaned with xylene before and after use

Knives should no be allowed to rust

Never lend or borrow a microtome knife to avoid misuse

Any 5 (5mrks)

Slide

(a) Identify the spot shown below

(b) Give 5 necessary care and maintenance practices for microtomes:

Answers;.

(a) Sliding microtome (1mrk)

(b) Remove the knife from the microtome after use

Clean the microtome with a piece of cloth soaked in Xylene after use

Clean the wax/tissue pieces with a camel hair brush after use.

Cover the microtome with a plastic bag and keep in a dust free room

Keep microtomes on a stable bench to avoid vibrations (5mrks)

Slide 17

(a) Identify the spot shown below

(b) Give three advantages of the above spot

(c) Give one disadvantage of the above spot

Answers;.

(a) Base sledge microtome (1mrk)

(b) Heavy and stable with no vibrations, Angle of the knife is adjustable, Knife used is long
hence requires less honing, The knife holding clamps are adjustable and allow the tilt and the
angle of the knife to be easily set. (3mrks)

(c) Slower in use (1mrk)

Slide 18

(a) Identify the spot shown below

(b) Give three advantages of the above spot

Answers;

(a) Rocking microtome (1mrk)

(b) Can cut sections from small blocks of any tissue type

The mechanism is simple

The machines literally last lifetime

In emergency can be adapted for frozen sections by freezing the tissue with ethyl chloride
spray. (3mrks)
Slide 19

(a) Identify the spot shown below

(b) State it's use

Answers;

(a) Heating Mantel (1mrk)

(b) Used to heat or temper certain media in glass vessels. (1mrk)

Slide 20

(a) Identify the tissue processing step shown below

(b) What is the meaning of the step you have identified in (a) above

(c) What is usually the aim of the step above?

(d) The use of various fixatives depends on.

(e) Give four qualities of a good fixative

(f) Give four effects of fixatives on tissues

Answers;

(a) Fixation (1mrk)

(b) The process of using chemical substance (solutions) to preserve tissues (1mrk)

(c) To stop post mortem changes by preserving the structures, shape, relationship and
constituent of tissues and cells in as life like manner as possible. (1mrk)

(d) The type of tissue, Urgency of investigation, Tissue structures required for demonstration
and its side effects both to tissue and user, Type of straining procedure. (3mrks)
(e) It must kill the tissue cells quickly (to avoid further metabolism), Must inhibit autolysis by
inactivating enzymes, Must stop Putrefaction (anti-bacterial), Must render soluble substances
of the cell insoluble. (4mrks)

(f) Inactivation of enzymes, Anti- bacterial, Increase of refractive index, Introduction of

pigments, Health hazards, Swelling, Shrinkage, Mordanting effect. Any 4 (4mrks)

Slide 21

(a) Identify the tissue processing step shown below

(b) What is Putrefaction:?

(c) What is Autolysis?

(d) Give three Signs of autolysis

Answers;

(a) Sectioning

(b) This is the breakdown of tissue after death or removal of tissue/cells by the action of
bacteria.

(c) It is the destruction of tissue by its own enzymes.

(d) The nucleus first condenses in the process called Pyknosis. It then fragments (Karyorrhesis)
and finally disappears in the process called Karyolysis, The cytoplasm swells, becomes
granular and eventually becomes a homogenous mass with the loss of normal staining power,
The glycogen within the cytoplasm diminishes or diffuses out of the cell leaving an empty
space (3mrks)
Slide 22

(a) What type of a fixative is the spot shown below?

(b) What is it used for

(c) Give three other examples of fixatives that can serve the same purpose as the spot shown
above

(d) Give four Factors that affect the quality of fixation:

Answers;

(a) Nuclear fixative

(b) Used to preserve the structures within the nucleus.

(c) Fleming’s fluid, Clark’s fluid, Sanfelice fluid

(d) Buffers and pH, Duration of fixation and size of specimen, Temperature of fixation,
Concentration of the fixative, Osmolality of the fixative and ionic composition.

Slide 23

(a) State the use of the spot below in tissue processing

(b) State one advantage of the spot in the use you have named above

(c) State one disadvantage of the spot in the use you have named above

(d) What is decalcification

(e) Give three examples of tissues that may need decalcification

(f) The best fixative for tissue to be decalcified is?

(g) Name three methods used for decalcification

Answers;

(a) Decalcifying agent (1mrk)

(b) Rapid in action. (1mrk)

(c) Causes damage to tissue and inhibit nucleus staining if left in the solution for a long time.
(1mrk)

(d) This is the removal of Calcium ions from a tissue to make it soft for easy section cutting
and avoid damage to the microtome knife (2mrks)

(e) Bone, Teeth, Cartilage, Calcified soft tissues such as Lymphoid and lungs due to
Tuberculosis infection, ovarian cyst and thyroid gland. (3mrks)

(f) 10% formal saline (1mrk)

(g) Use of mineral acid, Ion exchange resin, Chelating agents, Electrolytic Method. (3mrks)
Slide 24

(a) The method of decalcification that utilizes the spot below is

(b) State it's mode of action

(c) What is the meaning of EDTA in full

Answers;

(a) Chelating agents: (1mrk)

(b) These are chemical substances that are able to bind calcium to form soluble non-ionized
compounds examples of this agents are: (2mrks)

(c) Ethylene Diamine tetra acetic acid (EDTA). (1mrk)

Slide 25

(a) Identify the method of decalcification shown below

(b) Briefly describe how decalcification process takes place using the above method

(c) Give two reasons why the above method is not highly recommended

(d) Give two disadvantages of using the mechanical method to detect the endpoint of
decalcification

(e) Give one advantages of using the mechanical method to detect the endpoint of
decalcification
(f) State the principle of the Radiological Method of determining the end point of
decalcification.

Answers;

(a) Electrolysis: (1mrk)

(b) Calcium ions are removed from tissue by a decalcifying fluid these ions will then move to
the Cathode. The negatively charged ions move to the anode. (1mrk)

(c) Tisues normally get charred due to use of electric current, it is expensive. (2mrk)

(d) This method is very inaccurate and can lead to distortion of tissues, It’s not possible to
detect small amount of calcium (2mrk)

(e) It’s not expensive and easy to carry out. (1mrk)

(f) Calcium ions are radio opaque and can be detected through X –rays. (2mrk)

Slide 26

(a) Identify the tissue processing step shown below

(b) Give three reagents that can be used for dehydration

Answers;

(a) Dehydration (1mrk)

(b) Alcohol such as (ethyl, methyl, iso-propanol, and Butyl), Acetone, Pyridine, Cellulose,
Dioxane (Diethylene dioxide). (3mrks)

Slide 27

(a) State the use of the spot below in tissue processing

(b) State there advantages of the spot in the use you have stated above

(c) State there disadvantages of the spot in the use you have stated above
(d) What is clearing?

(e) Name three other agents that can be used for the same purpose as the spot shown

Answers;

(a) Clearing (1mrk)

(b) Tissue are made transparent, Rapid in action taking 2-6 hours, Not expensive compared to
other clearing agents., Easily removed form tissues during impregnation with supporting
media, No effects on subsequent tissue staining (3mrks)

(c) Tissue become brittle on long immersion in xylene, It causes excessive, shrinkage on
delicate tissues, It is highly flammable (3mrks)

(d) This is the removal of alcohols or any other dehydrating agent from tissues.

(e) Toluene, Chloroform, Cedar wood oil, Paraffin oil and Aniline oil. (3mrks)
Slide 28

(a) Classify the stain below into either basic or acidic

(b) Give two examples of basic stains

(c) Give two examples of acidic stains

(d) Give two examples of neutral stains

(e) What are natural dyes

(f) Give three examples of Natural dyes:

Answers;

(a) Basic (1mrk)

(b) Methylene blue and Haematoxylin and Basic fuchsin. Any 2 (2mrks)

(c) Eosin, Acid fuchsin and orange G. Any 2 (2mrks)

(d) Leishman, Giemsa and May Grunwald (Romanowsky stains) Any 2 (2mrks)

(e) These are dyes obtained from plants and animals specifically insects. (1mrk)

(f) Haematoxylin, Carmine, Orcein, Litmus, Saffron and Brazilin. (3mrks)

Slide 29

(a) State the use of the mordant in the staining reaction below
(b) Give three examples of histological mordants

(c) What is direct staining?

Answers;

(a) Facilitates the staining reaction by forming a link between the dye and the tissue. (1mrk)

(b) Iron (ferric ammonium sulphate, ferric chloride) Aluminium (ammonium aluminium)
Tungstate ( Phosphotungstic acid), Chromium, Iodine. (3mrks)

(c) Staining method where the dye is taken up by the tissue structures without addition of a
mordant. (1mrk)
Slide 30

(a) Identify the stains used to stain the tissue below

(b) What is Vital staining

(c) What is Intra- viral staining:

(d) What is Supra – vital staining:

(e) What is Progressive staining?

(f) What is Regressive staining?

(g) Give four factors responsible for staining variations.

Answers;

(a) Hematoxylin and Eosin (1mrk)

(b) This involves the staining of living cells. The cells can either be stained inside or outside
the body. (1mrk)

(c) It involves the staining of living cells while still inside the body. (1mrk)

(d) This involves removal of a tissue form the body and stained immediately when cells are
still living. (1mrk)

(e) It is selective staining of tissue where no differentiation is required. The tissue structures
are stained in a definite order, so that at the end of the staining period a differential colour is
attained. (1mrk)

(f) It involves over staining of tissues with a stain then differentiated. (1mrk)

(g) PH of the solvent of the stain,. Temperature at which the staining is administered,. Nature
of tissue e.g. density, binding sites,. Age of the stain, Solubility of the stain, some stains have
the ability to dissolve in certain tissue structures than the original solvent. Time, certain
tissue structures take up stains within the shortest time possible and others require longer
period to stain. Concentration of the stain. Any 4 (4mrks)