CBC interpretation

Do you know : How to evaluate anemia using MCV, RDW and RETIC count How to assess different RBC shapes reported in the PBS How to deal with leukocyte abnormalities seen on PBS The causes of thrombocytosis and thrombocytopenia

Evaluating Anemia Role of MCV Formula (2-10 yrs old) mean corpuscular volume Formula (2-10 yrs old) Lower limit: 70 fL + age in years Upper limit: 84 fL + ( age in yrs x 0.6 ), until upper limit of 96 is reached

Evaluating Anemia MCH (Mean Corpuscular Hb) MCHC (Mean Corpuscular Hb conc) normo/hyper/hypo chromic Used in iron deficiency - Spherocytosis -

What’s the MCV range? Give LL and UL 7 year old

answer LL: 77 fL UL: 88.2 fL

RETICULOCYTE COUNT Expressed as % of circulating rbc’s Take up reticulin stain (supravital): bec of inc RNA N = 0.5 % to 1.5 % or = .005 to .015

RETICULOCYTE COUNT Provide crucial info on RATE of red cell production 2 broad classes of anemias 2 red cell loss or destruction – inc retic - e.g. hemolysis, blood loss Dec red cell production – dec retic e.g. aplastic, iron deficiency

Reticulocyte index Anemic patient --> increased retic so have to correct: retic observed x px Hct / 0.45 Example: Hb 50 Hct 0.15 Retic count=.045= 4.5 % Corrected retic = 4.5% x .15/.45 = 1.5 % ( N = 0.5-1.5%)

Absolute Retic Count More accurate Compute as ff: RBC (in n x 1012 ) x # retic/1000 rbc x 1000 Normal = 40,000 – 100,000/uL

Quiz Compute for absolute retic count : Hb 90 RBC 3 x 1012 /L

Answer 45,000 retics / uL

Anemia based on MCV and retic Increased MCV High retic Low retic Decreased MCV Normal MCV

Increased MCV Increased Retic Acute blood loss Hemolysis - cased by inc # retics  retics have a large cellular volume

Anemia based on MCV and retic Increased MCV High retic Low retic Decreased MCV Normal MCV

Inc MCV, low retic Bone Marrow Failure Retic count greatly dec for degree of anemia ------------------------------------------- ---------------------- E.g. Known case of Aplastic anemia RBC 1.73 Hb 52 Hct 0.15 Retic = 1 % or 0.010 > Compute for corrected retic count % absolute retic

Inc MCV, Dec Retic 2. Megaloblastic disorders 3. Alcohol Folate and Vit B 12 deficiency Other things seen : Hypersegmentation of PMN’s Macroovalocytosis Megaloblastic changes in BM 3. Alcohol direct toxic effect on BM

Inc MCV, dec retic Anti-metabolites Hypothyroidism Methotrexate (folic acid anti-metabolite) Co-trimoxazole Hypothyroidism a. Causes red cell hypoplasia Usually normocytic/normochromic Macrocytosis may develop

Decreased MCV Caused by insufficient Hb synthesis Mostly caused by: Iron deficiency Inability to use iron Chronic disease Thalassemia Lead poisoning Sideroblastic anemia

Decreased MCV Increased retic Normal /decreased retic Thalassemia Fe deficiency Anemia of Chronic Disease Thalassemia trait Sideroblastic anemia hardest differentials !

Iron deficiency RDW serum Fe  MCV  anemia Common cause in 1-3 years of age As iron stores become depleted: RDW serum Fe  MCV  anemia First manifestation : RDW

Iron deficiency Reasonable approach: Oral iron replacement (+) response: Hb by 15-20 in 1 month PRESUMPTIVE DX MADE !

RED CELL DISTRIBUTION WIDTH Quantitative measure of anisocytosis The greater the # of sizes of rbc’s, the higher the RDW Normal = 11.5-14.5 No subnormal values have been reported

RDW HIGH ( FGHI- C ) Iron deficiency Hb H disease Fragmentation G-6PD Chronic disease

Decreased MCV Increased retic Normal /decreased retic Thalassemia Normal /decreased retic Fe deficiency Anemia of Chronic Disease Thalassemia trait Sideroblastic anemia hardest differentials !

Anemia of Chronic Disease Mild to moderate anemia (Hb 100 – 110) Slight inc RDW; dec Fe, inc Ferritin Px has chronic INFLAMMATION Disturbs iron recycling  iron left trapped in RES Cytokines IL-1, IL-6  inc ferritin syn  empty ferritin shells provide excess iron storage capacity  iron sequestered in RES

MCV NORMAL

MCV NORMAL

MCV NORMAL

Renal Disease Cause: erythropoeitin insufficiency Serum inhibitors of erythropoeisis accumulate in uremic patients Acanthocytosis Shortened rbc life span When BUN > 150 mg/dL

PLATELETS Cytoplasmic fragments ; no nucleus Life span = 7-10 days 1/3 in spleen, 2/3 in circulation Size= 1 – 4 um Large Young 2 peripheral destruction Small or normal Production defect

THROMBOCYTOSIS Platelet count > 600,000 Rarely causes complications ! Therefore, antiplatelet tx is rarely indicated Kawasaki is an exception

THROMBOCYTOSIS Hemolytic anemia Post-splenectomy Hemorrhage Post-op Infection Iron def anemia Vit E deficiency Vascular Collagen disorders Post-splenectomy Post-op Inflammatory Bowel Dis Trauma Tumors Syndrome, kawasaki Syndrome, nephrotic Syndrome, myeloprolif HIV is the PITS !

THROMBOCYTOPENIA Immune Platelet Destruction Infections Platelet clumping - falsely low - 2 inadequate coagulation

RBC abnormalities Anisocytosis Poikilocytosis Microcytes Macrocytes Normocytes Poikilocytosis Different shapes

RBC abnormalities Severe hemolysis Nucleated rbc’s Schistocytes: helmet cells, triangle cells, bite cells Spherocytes (immune mediated) acanthocytes

Spherocytes / acanthocytes

schistocytes

Abn RBC shapes Target cells Hypochrom ovalocyte Elliptocyte Liver disease Thalassemia Iron deficiency Post-splenectomy Elliptocyte Elliptocytosis Megaloblastic anemia Myelofibrosis Normochrom ovalocyte Ovalocytosis Thalassemia Hypochrom ovalocyte Iron deficiency Macrocytic ovalocyte Megaloblastic anemia

Target cells/ elliptocytes

Abn RBC shapes Blister cell Tailed RBC Tear drop Schistocytes Microangiopathic hemolytic anemia Tailed RBC Megaloblastic anemias Iron deficiency Tear drop Hypersplenism Thalassemia Hemolytic Anemia Schistocytes hemolytic anemia Hypersplenism Megaloblastic anemia Thalassemia Acute Leukemia Post severe burns

1/4 point quiz show 10 year old with Hb 80, WBC 9 plt 350. On co-tri for repeated UTI. MCV 102 MCH 340 Retic ct 0.002 What is most likely diagnosis ? Fe deficiency Megaloblastic anemia Diamond Blackfan Anemia Hemolytic anemia

Answer B MEGALOBLASTIC ANEMIA (Prob 2 folate def)

2/4 Quiz show The ff is a cause of thrombocytosis A. Immune thrombocytopenic purpura B. Pregnancy C. Iron deficiency anemia D. Renal failure

Iron deficiency anemia ANSWER C Iron deficiency anemia

¾ QUIZ show Compute absolute retic count Hb 45 RBC 1.5 x 1012 / L

ANSWER 24,000 / uL

4/4 Quiz show Which presents as a microcytic anemia B-thalassemia Hemolytic Anemia Aplastic Anemia Anemia 2 blood loss

ANSWER A B- Thalassemia

The End