This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Haematology, Subject name: Pathology
LAP score is maximum in? 
Select and explain. 
A. CML, B. AML, C. Essential thrombocytosis, D. Polycythemia vera
D: Polycythemia vera
Answer: D: Polycythemia vera 
Explanation: Answwr is option 4 A Leukocyte Alkaline Phosphatase (LAP) score is still requested from the hematology laboratory as an aid in differential diagnosis in the peripheral hospital setting where molecular biology techniques are not readily available. The LAP score is usually decreased in chronic myelogenous leukemia and paroxysmal nocturnal hemoglobinuria, while it is increased in leukemoid reaction and polycythemia vera. www.mlo-online.com