This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Immunity, Subject name: Pathology
Lymphocyte phenotype test done for? 
Select and explain. 
A. Agammaglobinemia, B. SCID, C. Sepsis, D. Acute leukemia
B: SCID
Answer: B: SCID 
Explanation: Ans. (b) SCID(Ref: HENRY'S Clinical Diagnosis and Management by Laboratory Methods; 22ned ed/ pg 944-945)Lymphocyte phenotyping for assessing immune deficiency includes CD3 (pan T cell), CD4 (T helper subset), CD8 (T cytotoxic/suppressor subset), CD 19 (pan B cell), CD 16/56 (pan NK cell) and other cell surface markers as required based on clinical data. This analysis is indicated in diagnosis and monitoring of immunodeficiencies and immunotherapy in children and adults