Which is true regarding bleeding time?

Correct Answer: C

Rationale: The correct answer is C because bleeding time evaluates platelet function in vivo by measuring the time it takes for a small, standardized skin incision to stop bleeding. This test directly assesses the primary hemostasis process mediated by platelets. Choice A is incorrect because bleeding time can be influenced by various factors, making it less reliable and reproducible. Choice B is incorrect because bleeding time is typically evaluated using a stopwatch, not an optical densitometer. Choice D is incorrect because bleeding time is not a commonly ordered test due to its limitations and variability in results.

Correct Answer: A

Rationale: Neutrophilia is the correct answer for chronic bacterial infection. Neutrophils are the first responders to bacterial infections, leading to an increase in their count. Basophils are involved in allergic reactions, not bacterial infections. Lymphocytosis is seen in viral infections. Eosinophilia is associated with parasitic infections and allergic responses.

Correct Answer: D

Rationale: Koilonychias, characterized by spoon-shaped nails, is specific to iron deficiency anemia due to impaired nail growth. In hemolytic anemia, sickle cell disease, and thalassemia major, nail abnormalities are not typically observed. Iron deficiency leads to brittle, spoon-shaped nails. Consequently, option D is the correct answer.

Correct Answer: B

Rationale: The correct answer is B: Leukemoid reaction. Döhle bodies are blue-gray cytoplasmic inclusions seen in neutrophils, indicating rough endoplasmic reticulum disruption. Leukemoid reaction is a benign condition with elevated white blood cell count due to infections, inflammation, or stress. In chronic myeloid leukemia (A), abnormal myeloid cells are present but not Döhle bodies. Chediak-Higashi syndrome (C) is a rare genetic disorder with giant granules in neutrophils, not Döhle bodies. Infectious mononucleosis (D) shows atypical lymphocytes but not Döhle bodies.

Correct Answer: C

Rationale: The correct answer is C: Partial Thromboplastin Time (PTT). Hemophilia is a bleeding disorder due to deficiency of clotting factors. PTT specifically measures the intrinsic pathway of coagulation, which is affected in hemophilia. Prothrombin time (A) measures the extrinsic pathway, not specific for hemophilia. Bleeding time (B) assesses platelet function, not relevant for hemophilia. Platelet count (D) evaluates the number of platelets, not the clotting factor deficiency seen in hemophilia.