Initial and Additional Laboratory Tests for Immunodeficiency
Type | Initial Tests | Additional Tests |
|---|---|---|
IgG, IgM, IgA, and IgE levels Isohemagglutinin titers Antibody response to vaccine antigens (eg, Haemophilus influenzae type b, tetanus, diphtheria, conjugated and nonconjugated pneumococcal, and meningococcal antigens) | B-cell phenotyping and count using flow cytometry and monoclonal antibodies to B cells Flow cytometry for CD40 and CD40 ligand Evaluation for mutations in various genes, including BTK and NEMO Sweat test | |
Absolute lymphocyte count Delayed hypersensitivity skin tests (eg, using Candida) Chest radiograph for size of thymus in infants only | T-cell phenotyping and count using flow cytometry and monoclonal antibodies to T cells and subsets T-cell proliferative response to mitogens TREC test (a genetic test that identifies infants with abnormal T cells or a low T-cell count due to SCID or other disorders) | |
Phagocytic cell count and morphology | Flow cytometric oxidative burst measurement using dihydrorhodamine 123 (DHR) or nitroblue tetrazolium (NBT) Flow cytometry for CD18 and CD15 Neutrophil chemotaxis | |
C3 level C4 level CH50 activity (for total activity of the classical pathway) and AH50 activity (for total activity of the alternate complement pathways) C1 inhibitor level and function C1q | Specific component assays | |
AH50 = alternate complement hemolytic assay; BTK = Bruton tyrosine kinase; C = complement; CH = hemolytic complement; Ig = immunoglobulin; NEMO = nuclear factor–kappa-B essential modulator; SCID = severe combined immunodeficiency; TREC = T-cell receptor excision circle. | ||