Abnormally high LAP score is seen in -

Answer is option 1, polycythemia SECTIONS Approach Considerations The Polycythemia Vera Study Group (PVSG) was the first to set rigorous criteria for the diagnosis of polycythemia vera (PV) in the 1970s. With the establishment of polymerase chain reaction (PCR)-based methods for detecting the JAK2 V617F mutation, this may become the first molecular diagnostic marker for PV, similar to BCR/ABL for chronic myelogenous leukemia (CML). However, because of a paucity of centers doing red blood cell mass measurements, demonstrating an elevated red blood cell mass continues to become more difficult. The diagnostic criteria set by the PVSG are organized into two categories, A and B. The diagnosis of PV is established if all three category A criteria are present, or if criteria A1 plus A2 plus any two criteria from category B are present. Category A criteria are as follows: Total red blood cell mass >=36 mL/kg in males or >=32 mL/kg in females Aerial oxygen saturation >=92% Splenomegaly Category B criteria are as follows: Thrombocytosis, with platelet count >400,000/mL Leukocytosis, with a white blood cell count >12,000/mL Increased leukocyte alkaline phosphatase (ALP) >100 U/L emedicine.medscape.com