A Simple Technic for Counting Megakaryocytes.

Abstract

From an evenly-suspended marrow specimen, fill a Sahli hemoglobin pipette to the 20 cmm. mark and blow contents onto a slide to form a thick drop. Spread an area of about 1.5 x 3 cm. Place in incubator overnight. Immerse in 5% formalin in 1% acetic acid until erythrocytes are lysed and drop is grayish. Rinse with water and then with phosphate buffer, pH 6.4. Stain with Wright''s alone for 2-3 min. Add buffer-phosphate solution and stain 60-90 minutes. Wash in water and air dry. Spread thin film of immersion oil over smear and examine with 200 X. Count all megakaryocytes in the specimen and multiply by 50 to express as number per ml. Morphology is fairly well preserved. Study by this technique of number of megakaryocytes in normal and pathologic marrows is not yet complete. Preliminary results indicate that the normal range is between 500 and 4000 per ml.