This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Leukemia, Subject name: Medicine
Which one of the following laboratory test differentiates leukamoid reaction from chronic myeloid leukemia? 
Select and explain. 
A. LAP (leukocyte alkaline phosphatase), B. LCA (leukocyte common antigen), C. MPO (myelo-peroxidase), D. TRPA (tartrate resistant alkaline phosphatas
A: LAP (leukocyte alkaline phosphatase)
Answer: A: LAP (leukocyte alkaline phosphatase) 
Explanation: Ans. is 'a' i.e., LAP (leukocyte alkaline phosphatase) o A leukemoid reaction is an exuberant form of ieucocytosiswith leucocyte count upto 50000/mm3, that may follow infections.It is difficult to distinguish leukemoid reaction from leukemia.Absence of Philadelphia chromosome and increase in leucocyte alkaline phosphatase score rules out CML. CMLLeukemoidpH chromosome+ve-veALPDecreasedIncreased