For an infant with warning signs of immunodeficiency, what is the initial laboratory evaluation?

For an infant with warning signs of immunodeficiency, what is the initial laboratory evaluation?

• A. Candida skin test and lymphocyte surface markers
• B. CBC with differential and platelets
• C. Refer to immunologist for evaluation
• D. Otorhinolaryngology referral

Answer: (B)

Screening for suspected immunodeficiency in an infant starts with a readily available hematologic screen. A complete blood count with differential and platelets provides the total white cell count and the breakdown of cell types (including lymphocytes and neutrophils) as well as the platelet count. This basic profile can reveal lymphopenia or other cytopenias that hint at an immune problem or bone marrow issue and helps guide the next, more specific tests. Specialized assessments like a Candida skin test or lymphocyte surface markers are informative only after an initial CBC shows abnormalities, and jumping straight to an immunologist referral isn’t necessary without objective screening data. So the initial evaluation should be the CBC with differential and platelets.

Screening for suspected immunodeficiency in an infant starts with a readily available hematologic screen. A complete blood count with differential and platelets provides the total white cell count and the breakdown of cell types (including lymphocytes and neutrophils) as well as the platelet count. This basic profile can reveal lymphopenia or other cytopenias that hint at an immune problem or bone marrow issue and helps guide the next, more specific tests. Specialized assessments like a Candida skin test or lymphocyte surface markers are informative only after an initial CBC shows abnormalities, and jumping straight to an immunologist referral isn’t necessary without objective screening data. So the initial evaluation should be the CBC with differential and platelets.