CBC interpretation

CBC interpretation objectives

 Safe CBC interpretation

 Approach to Anemia

 Diagnosis and highlight about polycythemia

 Diagnosis and highlight about thrombocytopenia

 Diagnosis and highlight about Thrombocytosis

 Diagnosis and highlight about neutropenia and leukopenia.

 Diagnosis and highlight about Pancytopenia

 The major components of CBC are:

1-Hb2-WBC3-plateltes

If all major components are normal, then it is very less likely you miss a serious disease.

 Safe CBC interpretation:

1- look at Hb>>if low >> look at other major components (WBCs and Platelets) to not miss a
bone marrow disease.
2- if there is no striking abnormality of WBC and platelet then check MCV to classify the anemia
into microcytic, normocytic or macrocytic.
3- some references recommend to check reticulocyte before MCV to not miss hemolytic anemia
but not practical.
 Anemia
 Anemia Classification based on MCV:

 Helpful parameters to diagnose the underlying cause of anemia

 Size of red blood cells (MCV): (small/ normal/ big)
 Abnormal cells on microscopic examination (like blast cells in leukemia)
 Status of leukocytes and platelets (bone marrow function)
 Reticulocyte count (ability of marrow to respond to anemia)>> can help in hemolytic
anemia (if high) and in marrow suppression (if low).
 Evidence of destruction(hemolysis) >> (elevated LDH and indirect bilirubin)

o Microcytic anemia

 features might help in distinguishing between IDA and Thalassemia

feature IDA Thalassemia

RBC Low, Low normal High, High normal
MCV Mild to moderate low Very low (< 70)
(most likely above 70)
RDW Mostly High Mostly normal
Mentzer index: MCV/RBC > 13 < 13
IDA treatment

NOTE: Consider upper and lower GI endoscopy for any males (esp. elderly) and postmenopausal
women to R/O GI malignancy

 How much Hb increment is excepted with treatment?

-Around 2 to 4 g/dLevery three weeks.
(if Hb increased in slower rate >> check for ongoing bleeding??
 How long the treatment course is expected?
-Oral Fe TID (or less if not tolerated)
(around 6 weeks to correct anemia; and 6 months to replete Fe stores)

 Case: A 25 year- old lady, presented with 2 months H/O dizziness and fatigue

WBC .........................7. 0 4 – 11 x10.e9/L

RBC ......................... 3.7 L 4.2 – 5.5 x10.e12/L
HGB ........................ 90 L 120 – 160 g/L
HCT ......................... 28 L 42 – 52 %
MCV ....................... 73 L 80 – 94 fl
MCH .................. ......23.6 L 27 – 32 pg
MCHC ................. ... 320 320 – 360 g/L
RDW .................. ......15.8 H 11.5 – 14.5 %
PLT .................. ....... 330 140 – 450 x10.e9/L

Interpretation: Hypochromic microcytic anemia, Most likely: IDA

NOTE: Generally, The Hb threshold for blood transfusion for asymptomatic patient is <70 g/L
- - - - - - - - - - - - - - - - - - - -
 Case: A 29 years old female came for premarital checkup:

WBC .........................7. 0 4 – 11 x10.e9/L

RBC ......................... 5.3 L 4.2 – 5.5 x10.e12/L
HGB ........................ 101 L 120 – 160 g/L
HCT ......................... 40 L 42 – 52 %
MCV ....................... 62 L 80 – 94 fl
MCH .................. ......25.3 L 27 – 32 pg
MCHC ................. ... 320 320 – 360 g/L
RDW .................. ......14.1 11.5 – 14.5 %
PLT .................. ....... 339 140 – 450 x10.e9/L

interpretation: Hypochromic microcytic anemia, Most likely: Thalassemia

 -What you will order to confirm Dx?
Hemoglobin electrophoresis (HE).

-What do you expect in HE?

If HB A2 is > 3.5 >>> B-Thalassaemia Minor
If HB A2 is normal >>> alpha Thalassaemia Minor

o Normocytic anemia
DDxof normocytic anemia:
 Anemia of chronic inflammation or disease like:
1. Chronic kidney disease
2. autoimmune disorders
3. chronic infection
4. malignancy.
5. Combined Macrocytic and microcytic anemia in the same time.

Case : A 44 years old gentleman k\c of CKD , c.o generalized weakness:

WBC .........................8.5 4 – 11 x10.e9/L
RBC ......................... 5.1 L 4.2 – 5.5 x10.e12/L
HGB ........................ 107 L 120 – 160 g/L
HCT ......................... 41 L 42 – 52 %
MCV ....................... 88 80 – 94 fl
MCH .................. ......29 27 – 32 pg
MCHC ................. ... 340 320 – 360 g/L
RDW .................. ......14.1 11.5 – 14.5 %
PLT .................. ....... 339 140 – 450 x10.e9/L

Creatinine :……………188 H 53-106 μmol/L

Urea :……………………..7 2.5 to 7.1 mmol/L
eGFR: 34 mL/min/1.73 m2

interpretation: normocytic normochromic anemia, Most likely: secondary to chronic kidney

disease
 o MACROCYTIC ANEMIAS

 Megaloblastic :
• Vitamin B12 deficiency
• Folate deficiency
 Non-megaloblastic:
• Liver disease, Myelodysplastic syndrome, Increased reticulocyte count ,
Alcoholism >>> :BM suppression &macrocytosis independent of folate/B12 deficiency.or
liver cirrhosis

Case: 38 years old gentleman post gastric bypass, c.o fatigue

WBC .........................6.5 4 – 11 x10.e9/L

RBC ......................... 5.3 4.2 – 5.5 x10.e12/L
HGB ........................ 109 L 120 – 160 g/L
HCT ......................... 41 L 42 – 52 %
MCV ....................... 99 H 80 – 94 fl
MCH .................. ......42 H 27 – 32 pg
MCHC ................. ... 340 320 – 360 g/L
RDW .................. ......14.1 11.5 – 14.5 %
PLT .................. ....... 339 140 – 450 x10.e9/L

Interpretation: Macrocytic hyperchromic anemia, could be secondary to Vit b12 deficiency

 What you will order for this patient?

Vit b12 and folate level.
 Hemolytic anemia:
hemolytic anemia is suspected in a patient with chronic or new onset anemia with
reticulocytosis and not due to another obvious cause.

Case: 17 years old girl, c.o yellowish discoloration of skin and dark urine.
CBC
WBC ....... ..10.5 4 – 11 x10.e9/L
RBC .......... 4.9 4.2 – 5.5 x10.e12/L
HGB ........ 92 L 120 – 160 g/L
HCT ............ 36 L 42 – 52 %
MCV .......... 86 80 – 94 fl
MCH ............29 27 – 32 pg
MCHC ........ 352 320 – 360 g/L
RDW ..........14.3 11.5 – 14.5 %
PLT ............ 223 140 – 450 x10.e9/L

LFT:

Total bilirubin …………………..… 48 H (3- 17 umol/L)

Direct bilirubin ...................... 4 (0 – 5 umol/L)
Total protein ……………….. 73 (60-80 g/L)
Albumin ……………………………….38 (35-50 g/L)
Alkaline phosphatase …………...55 (50-136u/L)
Alanine aminotransferase ……40 (20-65 u/L)
Aspartate aminotransferase ...22 (10-31 u/L)
G.G. Transferase ………………….40 (5-55 u/L)
Interpretation: anemia (normocytic) associated with high indirect bilirubin.
What you will order?
Reticulocyte>> excepted to be high > 4%, LDH expected to be high and Haptoglobin expected to
be low.

Main DDx of high indirect bilirubin:

Blood Hemolysis,Gilbert's syndrome and Crigler–Najjarsyndrome( mainly in neonate).

Some Causes of hemolytic anemia :

Sickle cell anemia
G6PD
Thalassemia
Drugs
Autoimmune diseases
 Polycythemia:

Polycythemia is a laboratory finding in which there is an increased number of red blood

cells (RBC), along with an accompanying increase in the concentration of hemoglobin in
the peripheral blood.

 It could be primary (polycythemia vera) or secondary (in response to hypoxia)

Case: 37 years old lady c.o headache and plethora of face.

WBC .........................17.6 H4 – 11 x10.e9/L
RBC ......................... 7.2 H 4.2 – 5.5 x10.e12/L
HGB ........................ 19.3 H120 – 160 g/L
HCT ......................... 59 L 42 – 52 %
MCV ....................... 91 80 – 94 fl
MCH .................. ......30 27 – 32 pg
MCHC ................. ... 340 320 – 360 g/L
RDW .................. ......14.1 11.5 – 14.5 %
PLT .................. ....... 339 140 – 450 x10.e9/L

 What is the most important test to approach polycythemia?

-erythropoietin
 Low erythropoietin >> most likely primary polycythemia (polycythemia Vera)
 High erythropoietin >> most likely secondary polycythemia (smoking, COPD, high
altitude congestive heart failure ..)
Polycythemia Vera sometimes combined with high WBC and/or platelet.
 Thrombocytosis:

Case: A 48 years old lady c.o leg redness and hotness (cellulitis)

WBC .........................6.5 4 – 11 x10.e9/L

RBC ......................... 5.3 4.2 – 5.5 x10.e12/L
HGB ........................ 132 120 – 160 g/L
HCT ......................... 45 42 – 52 %
MCV ....................... 88 80 – 94 fl
MCH .................. ......31 27 – 32 pg
MCHC ................. ... 340 320 – 360 g/L
RDW .................. ......14.1 11.5 – 14.5 %
PLT .................. ....... 521 H140 – 450 x10.e9/L

Interpretation: Thrombocytosis, Most likely reactive based on Hx

 patients with elevated platelet counts, the initial diagnostic question is whether their
thrombocytosis is
1. reactive phenomenon (infection, post-surgery or Trauma..)
or
2. a marker for the presence of a hematologic disorder (chronic myeloproliferative
neoplasms...).

Thrombocytopenia
WBC .........................9.2 4 – 11 x10.e9/L
RBC ......................... 5.1 4.2 – 5.5 x10.e12/L
HGB ........................ 14.2 120 – 160 g/L
HCT ......................... 46 42 – 52 %
MCV ....................... 91 80 – 94 fl
MCH .................. ......30 27 – 32 pg
MCHC ................. ... 340 320 – 360 g/L
RDW .................. ......14.1 11.5 – 14.5 %
PLT .................. ....... 92 L140 – 450 x10.e9/L

 Thrombocytopenia (ie, platelet count <150,000/microL [150 x 109/L])

 Severe spontaneous bleeding is most likely with platelet counts <20,000 to 30,000/microL,
especially below 10,000/microL.
 Surgical bleeding generally may be a concern with platelet counts <50,000/microL
 DDx is wide and including bone marrow malignancy.
 Leukopenia and neutropenia:

Case: A 17 y old gentleman k/c of AML on chemotherapy c.o Fever

 We classify neutropenia based on NEU# (Absolute NeutrophilCount) not NEU% (Neutrophil

percentage)
 Leukopenia = low WBCs
 Neutropenia = low absolute neutrophils count (ANC)
 Leukopenia Neutropenia
 Febrile Neutropenia is a medical emergency
 Neutropenia classification is based on Absolute Neutrophil count (ANC)
 Mild < 1.5 K/uL ( 1500 cells / MicroL)
 Moderate <1.0 K/uL (1000 cells / MicroL)
 Sever < 0.5 K/uL ( 500 cells / MicroL)
Pancytopenia:

Case: 19 years old lady c.o weakness

WBC ............2.8 L 4 – 11 x10.e9/L

RBC ........... 3.2 4.2 – 5.5 x10.e12/L
HGB ............. 92L 120 – 160 g/L
HCT ............ 36 L 42 – 52 %
MCV .......... 86 80 – 94 fl
MCH ........... 29 27 – 32 pg
MCHC ........ 352 320 – 360 g/L
RDW ........ 14.3 11.5 – 14.5 %
PLT ............ 76 L140 – 450 x10.e9/L

 What are the common causes pancytopenia?

 Bone marrow malignancy
 Viral infection
 Drug induced
 Autoimmune disease

Usually a careful management is warranted in such case.

Good luck