Low LAP score may be seen in the following EXCEPT: September 2012

Ans. D i.e. Polycythemia vera Diagnostic criteria for polycythemia vera Accurate diagnosis of PV is critical because its treatment may require the use of drugs with the potential to cause leukemia. The patient is considered to have PV if all three major criteria are met; or if the first two major criteria and any two minor criteria are met. Major criteria - Red blood cell mass greater than 36 mL/ kg in males, greater than 32 mL/kg in females - Aerial oxygen level greater than 92% - Splenomegaly Minor criteria - Platelet count greater than 400,000/mm3 - WBC greater than 12,000/mm3 without fever or infection - Leukocyte alkaline phosphatase (LAP) score greater than 100 with increased blood serum levels of vitamin B12