<prompt> Low LAP score may be seen in the following EXCEPT:September 2012CMLParoxysmal nocturnal hemoglobinuriaAutoimmune hemolytic anemiaPolycythemia vera  <response>: Ans. D i.e. Polycythemia veraDiagnostic criteria for polycythemia veraAccurate 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 mLkg in females- Aerial oxygen level greater than 92- SplenomegalyMinor criteria- Platelet count greater than 400,000mm3- WBC greater than 12,000mm3 without fever or infection- Leukocyte alkaline phosphatase LAP score greater than 100 with increased blood serum levels of vitamin B12 