Immunology Tests Directory
Explore a practical guide to autoimmune serology, allergy investigations, immunoglobulins, complement, immune deficiency and specialized immunologic tests. Learn what each investigation detects, how results are used and where interpretation requires clinical correlation.
Browse Immunology Investigations
Loading...Antinuclear Antibody (ANA)
Screening investigation for antibodies associated with systemic autoimmune rheumatic diseases.
Clinical interpretation
Interpret with symptoms, titre, staining pattern and method. A positive ANA can occur in healthy individuals and does not independently diagnose systemic autoimmune disease.
ANA by Indirect Immunofluorescence (IIF)
Detects antinuclear reactivity using a substrate such as HEp-2 cells.
What to report
Report titre and staining pattern according to the validated laboratory protocol. Pattern nomenclature and clinical associations should be used cautiously; follow-up testing depends on clinical suspicion.
Extractable Nuclear Antigen (ENA) Profile
May include antibodies to Sm, RNP, SSA/Ro, SSB/La, Scl-70 and Jo-1, depending on the panel.
Clinical interpretation
Individual antibody results are more informative than the panel name alone. Not every laboratory includes the same antigens; review the actual assay composition.
Anti-dsDNA Antibody
Measures antibodies against double-stranded DNA, associated particularly with systemic lupus erythematosus.
Clinical interpretation
Specificity and sensitivity vary by method. Results may support SLE assessment and selected disease monitoring but must be interpreted with clinical findings and other investigations.
Anti-Sm Antibody
Detects antibodies to Smith antigen, associated with systemic lupus erythematosus.
Clinical interpretation
Anti-Sm can be relatively specific for SLE, but sensitivity is limited. A negative result does not exclude the disease.
Anti-SSA/Ro and Anti-SSB/La
Autoantibodies associated with Sjögren disease and other connective tissue diseases.
Clinical interpretation
Interpret with symptoms and other findings. SSA/Ro testing may be relevant in selected pregnancy assessments because of fetal and neonatal risks associated with maternal antibodies.
Anti-Scl-70 (Anti-Topoisomerase I)
Investigates an antibody associated with systemic sclerosis.
Clinical interpretation
Pretest probability and assay specificity matter, especially with low-positive results. Unexpected findings may require confirmation using an appropriate method.
Anti-Centromere Antibody
Associated with selected systemic sclerosis phenotypes and other clinical settings.
Clinical interpretation
Interpret with clinical features and the test method. A centromere staining pattern on ANA IIF is not identical to a specific antigen assay.
Anti-Jo-1 and Myositis Antibodies
Investigates selected antibodies associated with inflammatory myopathies and antisynthetase syndrome.
Clinical interpretation
Myositis panels vary in their included antibodies. Weak-positive results can be nonspecific and should be correlated with muscle symptoms, enzymes and other clinical findings.
ANCA by Indirect Immunofluorescence
Assesses antineutrophil cytoplasmic antibody staining patterns.
Clinical interpretation
Patterns such as c-ANCA and p-ANCA are not equivalent to antigen-specific PR3 and MPO antibodies. Results may occur in conditions other than vasculitis.
PR3-ANCA
Measures antibodies against proteinase 3, associated with some ANCA-associated vasculitides.
Clinical interpretation
Interpret with clinical presentation, urinalysis, kidney function and other investigations. A positive result alone does not establish vasculitis.
MPO-ANCA
Measures antibodies against myeloperoxidase.
Clinical interpretation
Can support investigation of selected ANCA-associated vasculitides. Positivity can occur in other diseases and with some medications; clinical correlation is essential.
Anti-Glomerular Basement Membrane (Anti-GBM)
Detects antibodies associated with anti-GBM disease.
Clinical interpretation
May be urgently relevant in rapidly progressive glomerulonephritis or pulmonary-renal syndromes. Results must be assessed alongside renal and respiratory findings.
Rheumatoid Factor (RF)
Measures antibodies commonly used in the evaluation of rheumatoid arthritis.
Clinical interpretation
RF is not specific for rheumatoid arthritis and can be positive in other conditions and in some healthy individuals. A negative result does not exclude RA.
Anti-CCP Antibody
Detects antibodies to cyclic citrullinated peptides and supports RA evaluation.
Clinical interpretation
Anti-CCP is generally more specific for RA than RF, but results must be interpreted with symptoms and examination. A positive test alone is not a complete diagnosis.
Anti-MCV Antibody
Measures antibodies against mutated citrullinated vimentin in selected RA evaluations.
Clinical interpretation
This is an additional marker rather than a universal first-line test. Clinical usefulness and performance depend on the population and assay.
Total IgG, IgA and IgM
Quantifies major immunoglobulin classes.
Clinical interpretation
Used in evaluation of immune deficiency, recurrent infections and selected inflammatory or hematologic disorders. Age, protein loss, medication and clinical context affect interpretation.
IgE Total
Measures total circulating immunoglobulin E.
Clinical interpretation
Total IgE may be elevated in atopy and several other conditions. It does not identify the specific allergen and a normal value does not exclude allergic disease.
Complement C3
Measures a major component of the complement system.
Clinical interpretation
Low levels may reflect consumption or reduced production. Interpret with C4, kidney findings and the clinical context.
Complement C4
Measures a complement protein relevant to classical pathway activity.
Clinical interpretation
Low C4 can occur with complement consumption and some inherited deficiencies. C3, clinical history and additional tests may be needed to clarify the cause.
CH50 and AH50
Functional assays evaluating classical and alternative complement pathway activity.
Specimen considerations
Complement function can be affected by improper collection, storage or transport. Follow the testing laboratory's requirements closely, as some methods require rapid handling or frozen transport.
Allergen-Specific IgE
Measures IgE sensitization to selected inhalant, food or other allergens.
Clinical interpretation
A positive result indicates sensitization, not necessarily clinical allergy. Test selection should be guided by the history; indiscriminate panels can produce misleading findings.
Allergen Component Testing
Measures IgE against selected individual allergen proteins rather than whole extracts.
Clinical interpretation
Can help refine selected allergy assessments, including cross-reactivity or risk evaluation. Components must be selected according to clinical history and available evidence.
Skin Prick Testing
Assesses immediate skin reactivity to selected allergens.
Clinical interpretation
Must be performed and interpreted by trained personnel with appropriate controls and safety procedures. A positive skin response alone does not confirm symptomatic allergy.
Basophil Activation Test (BAT)
Measures activation markers on basophils after controlled allergen stimulation.
Clinical interpretation
A specialized functional test used in selected allergy investigations. Fresh specimen requirements, transport time, controls and validated laboratory protocols are critical.
Tryptase
Measures a mast-cell-associated enzyme, used in selected investigations of systemic mast-cell activation.
Clinical interpretation
Timing of acute and baseline samples matters. Interpretation depends on the clinical event and appropriate comparison with baseline values.
Anti-Tissue Transglutaminase IgA (tTG-IgA)
Common first-line serology for celiac disease in appropriate patients.
Clinical interpretation
Total IgA should be considered because IgA deficiency can cause a false-negative result. Testing is generally performed while the patient is consuming gluten, unless directed otherwise by the treating clinician.
Total IgA
Helps identify IgA deficiency when interpreting IgA-based celiac serology.
Clinical interpretation
If IgA deficiency is present, appropriate IgG-based celiac tests may be considered. Interpret results using age-appropriate reference intervals and clinical guidance.
Deamidated Gliadin Peptide Antibodies (DGP)
Measures IgA and/or IgG antibodies to deamidated gliadin peptides.
Clinical interpretation
May be useful in selected cases, including some patients with IgA deficiency. Test choice depends on age, clinical suspicion and the diagnostic pathway.
Anti-Saccharomyces cerevisiae Antibody (ASCA)
May be used as an adjunct in selected inflammatory bowel disease evaluations.
Clinical interpretation
ASCA is not diagnostic of Crohn disease on its own. It has limited sensitivity and should not replace clinical, endoscopic, imaging or histologic assessment.
Lymphocyte Subset Analysis
Quantifies selected T, B and NK cell populations.
Clinical interpretation
Used in selected primary or secondary immune deficiency assessments and immune monitoring. Absolute counts, age, medication and clinical history are important.
Specific Antibody Response
Assesses antibody responses to selected vaccine antigens when indicated.
Clinical interpretation
Requires a defined clinical question, appropriate timing and interpretation of pre- and post-immunization results when applicable. Thresholds depend on antigen and validated guidance.
IgG Subclasses
Measures IgG1, IgG2, IgG3 and IgG4.
Clinical interpretation
Subclasses may be considered in selected recurrent-infection evaluations. An isolated low result does not establish clinically significant immune deficiency without appropriate clinical assessment.
Anti-Thyroid Peroxidase (Anti-TPO)
Detects antibodies associated with autoimmune thyroid disease.
Clinical interpretation
Use with thyroid function tests and clinical findings. Antibody positivity does not itself indicate the degree of thyroid dysfunction.
Anti-Thyroglobulin Antibody
Detects antibodies against thyroglobulin.
Clinical interpretation
May support evaluation of autoimmune thyroid disease and can interfere with thyroglobulin assays used in selected thyroid cancer follow-up.
Anti-Mitochondrial Antibody (AMA)
Associated with primary biliary cholangitis in the appropriate clinical setting.
Clinical interpretation
Interpret with liver biochemistry, clinical findings and other relevant investigations. A positive antibody should be evaluated in context rather than treated as a stand-alone diagnosis.
Anti-Smooth Muscle Antibody (ASMA)
Used in evaluation of suspected autoimmune hepatitis.
Clinical interpretation
Low-level positivity may be nonspecific. Interpret with liver enzymes, IgG, ANA, clinical history and other causes of liver injury. A low titre alone does not establish autoimmune hepatitis.
Anti-Liver-Kidney Microsomal Antibody (Anti-LKM)
May support investigation of selected autoimmune hepatitis phenotypes.
Clinical interpretation
Interpret with the full liver workup and the specific antigen or method used. Antibody results are not sufficient in isolation to diagnose autoimmune liver disease.
Anti-Intrinsic Factor and Anti-Parietal Cell Antibodies
Investigates autoimmune mechanisms associated with pernicious anemia and autoimmune gastritis.
Clinical interpretation
Anti-intrinsic factor antibodies are generally more specific but less sensitive. Interpret with vitamin B12, blood count and clinical findings; parietal-cell antibodies are less specific.
Cryoglobulins
Detects immunoglobulins that precipitate at lower temperatures.
Specimen considerations
Strict temperature-controlled collection and processing are essential. Improper handling may cause false-negative results; coordinate requirements with the testing laboratory before collection.
Immunofixation Electrophoresis (IFE)
Identifies and characterizes monoclonal immunoglobulin patterns.
Clinical interpretation
Often used with protein electrophoresis and, when appropriate, serum free light chains. It supports investigation of monoclonal gammopathies but does not replace clinical assessment.
Serum Free Light Chains
Measures free kappa and lambda light chains and their ratio.
Clinical interpretation
Useful in selected plasma-cell disorder investigations. Kidney function and assay-specific reference intervals affect the results and ratio.
Anti-Phospholipid Antibodies
May include anticardiolipin and anti-beta-2 glycoprotein I antibodies.
Clinical interpretation
These tests are part of selected antiphospholipid syndrome evaluations, alongside lupus anticoagulant testing. Persistent positivity and appropriate clinical criteria are important.
Anti-CCP and Rheumatoid Factor Combined Profile
Combines two commonly used serologic markers in rheumatoid arthritis evaluation.
Clinical interpretation
Using both markers can provide complementary information, but neither confirms or excludes rheumatoid arthritis in isolation.
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