Interpreting The CBC Francisco F. Lopez, MD The 2005 Advanced Medical Underwriting Course January 14, 2005

Outline Definition Microcytic anemia Normocytic anemia Macrocytic anemia Algorithm

Definition Complete Blood Count is a blood test obtained in the peripheral vein that gives us a numerical value of the white and red cells and platelets, and a picture of what is going on in the bone marrow.

The CBC Mean Corpuscular Volume (MCV): the average volume of the red cells hematoctirt (L/L) x 1000 / red cell count (x10 12 /L) normocytic, microcytic, macrocytic Mean Corpuscular Hemoglobin (MCH): A measure of the hemoglobin concentration per red cell hemoglobin (g/L) / red cell count (x10 12 /L) Mean Corpuscular Hemoglobin Concentration (MCHC): The average concentration of hemoglobin per red cell hemoglobin (g/dL) / hematocrit (L/L) Red Cell Distribution Width (RDW): The range of red cell sizes measured within a sample

Case # 1 68y/o male with a cc: anemia and SOB. No melena or hematochezia. PE: unremarkable Hgb 10 hct 31 rbc 3.99 MCV 77.6 retic 2.2% Iron 2.8 (low), feritin 4.22 (low) TIBC 84 (high)

Case # 2 40y/o female cc: SOB x 1 week She was brought to the ER of AHMC

Laboratory test WBC12.1 (4.5 – 11 x 10 9 /L) RBC 2.18 (3.8 – 5.3 x 10 9 /L) Hgb62 (120 – 160 g/ L) Hct0.175 (0.35 – 0.47) MCV80.2(73 – 103 fL) Platelet212( x 10 9 /L)

Laboratory tests Iron 15.3 umol/L (6.6 – 30.4) TIBC 84 umol/L (44.8 – 80.6) Ferritin ng/ml (11 – 306.8) Retic count 3.4% (0.5 – 1.5%) Peripheral smear: anisocytosis and poikilocytosis, normochromic ESR 119 (0.0 – 20 mm/hr)

Laboratory tests Urea 40.9 ( ) Creatinine 1348 (62 – 106) Tx: dialysis

Case # 3 67 y/o male admitted at AHMC because of dizziness. He was ruled out for any cardiac or neurologic diseases. No gastrointestinal bleeding. Weight loss of 5 pounds. PE: normal Labs: Hgb 11.7; LDH 1184; Reticulocyte count 1.4; stool for occult blood negative

Vit B12 50 (low) TSH normal Folate normal Rx: methycobal 500mcg IM

Summary The CBC gives us a picture of what is going on in the bone marrow Not all anemia should be treated with iron Further diagnostic tests should be pursued to determine the cause of the anemia.