Laboratory Science Hematology and Blood Analysis 3

Question 1

What is the purpose of the reticulocyte count in hematology?

Accepted Answer

Assess bone marrow erythropoietic activity

Answer

Reticulocyte count reflects the rate of RBC production by bone marrow; elevated counts indicate accelerated erythropoiesis in response to anemia or blood loss.

Question 2

Which tube color is used for coagulation studies (PT/aPTT) in the US?

Accepted Answer

Light blue/sodium citrate

Answer

Light blue tubes contain sodium citrate (3.2%), which chelates calcium to prevent clotting; the 9:1 blood-to-anticoagulant ratio is critical for accurate coagulation testing.

Question 3

What morphological change in RBCs is described as 'target cells' (codocytes)?

Accepted Answer

RBCs with a central dense area surrounded by a pale ring and a dense outer rim

Answer

Target cells have a bulls-eye appearance (central density, pale ring, dense rim) due to excess membrane relative to hemoglobin, seen in thalassemia and liver disease.

Question 4

A patient with chronic kidney disease would most likely show which hematological finding?

Accepted Answer

Normochromic normocytic anemia due to decreased erythropoietin

Answer

Damaged kidneys produce less erythropoietin (EPO), reducing RBC production and causing normochromic normocytic anemia of chronic kidney disease.

Question 5

What is the order of blood tube draw for multiple specimens (correct order of draw)?

Accepted Answer

Citrate → SST/Gold → Heparin → EDTA

Answer

CLSI order of draw: Blood cultures → Citrate (blue) → SST/gold → Heparin (green) → EDTA (lavender) → Fluoride (gray) to prevent anticoagulant carryover.

Laboratory Science Practice Test

Laboratory Science Practice Test

Laboratory Science Hematology and Blood Analysis 3