<prompt> A 70 year old male presented with generalized lymphadenopathy. WBC count was 50,000mm3 and blood film showed 70 mature looking lymphocytes. Which is the next ideal investigation for clinching the diagnosis?Lymph node biopsyPeripheral blood immunophenotypingBone marrow aspirationPeripheral blood cytogenetics  <response>: In the given question, an elderly patient with generalized lymphadenopathy was found to have WBC count 50,000mm3 and blood film showed 70 mature looking lymphocytes. Most likely this is a case of Non-Hodgkin Lymphoma with spill over in the peripheral blood. Hence, next ideal investigation that should be done is immunophenotyping of Peripheral blood Lymphocytes. This is done to see the expression of various markers on the lymphocytes immunophenotype, performed by flow cytometry method. 