A proactive plan starts by matching the exact titers you need (MMR, varicella, hepatitis B, tetanus/diphtheria). For past exposure questions, add COVID-19 antibodies (spike ± nucleocapsid). For tuberculosis screening, choose a TB blood test (IGRA) such as QuantiFERON or T-SPOT. When infections are frequent or severe, add immunoglobulins (IgG/IgA/IgM), IgG subclasses, pneumococcal serotype responses, lymphocyte subsets, and complement. These labs support screening, documentation, and monitoring, but they do not diagnose active illness or replace clinical evaluation.
Signs, Symptoms & Related Situations
Testing choices and symptoms should be reviewed with a qualified clinician.
Why These Tests Matter
What testing can do
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Provide proof of immunity for schools, employers, and programs
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Detect TB infection (latent or active) via IGRA screening; unaffected by BCG vaccination
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Characterize immune status (immunoglobulins, subclasses, functional antibody) and guide next steps
What testing cannot do
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Diagnose active infection or confirm contagiousness
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Guarantee lifelong protection—antibodies can wane and cutoffs vary by disease/assay
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Replace vaccinations/boosters, imaging, or clinician judgment when indicated
What These Tests Measure (at a glance)
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Vaccine/Exposure Titers (IgG): Measles, Mumps, Rubella; Varicella-Zoster; Hepatitis B surface antibody (anti-HBs); Tetanus/Diphtheria; Hepatitis A IgG; others as requested.
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COVID-19 Antibodies: Spike (S) IgG for vaccine response/previous exposure; Nucleocapsid (N) IgG for prior infection; some panels include surrogate neutralizing activity.
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TB Blood Tests (IGRAs): QuantiFERON-TB Gold Plus or T-SPOT.TB—single visit, not affected by BCG; results are positive/negative/indeterminate and require clinical follow-up.
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Immunoglobulin Profile: IgG/IgA/IgM (± IgE); low levels can signal immune deficits, high levels may reflect inflammation.
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IgG Subclasses (1–4): supportive when total IgG is normal but infections persist; interpret with functional antibody testing.
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Functional Antibody Testing: Pneumococcal serotype IgG before/after vaccination to assess antibody production.
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Lymphocyte Subsets (Flow): CD3/CD4/CD8 T cells, CD19/20 B cells, CD16/56 NK cells—screens cellular immunity.
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Complement System: C3, C4, CH50 (± AH50) to evaluate classical/alternative pathway activity.
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Context labs: CBC with differential and CRP/ESR for infection/inflammation clues.
Quick Build Guide
| Goal |
Start with |
Add if needed |
| School/health-care onboarding |
MMR IgG • Varicella IgG • Hep B surface Ab • Tetanus/Diphtheria IgG |
Pertussis IgG if your program accepts it |
| Post-vaccine proof (Hep B) |
Hep B surface Ab (draw ≥3–4 weeks post-series) |
Repeat after booster if nonreactive (clinician-directed) |
| TB screening (employment/exposure) |
QuantiFERON-TB Gold Plus |
T-SPOT.TB if indeterminate or immunosuppressed |
| COVID-19 past exposure/response |
Spike IgG |
Nucleocapsid IgG ± Neutralizingactivity |
| Frequent infections—initial screen |
IgG/IgA/IgM • CBC with differential |
IgG Subclasses • Pneumococcal serotypes (pre/post) |
| Suspected complement issue |
C3 • C4 |
CH50 (± AH50) |
| Pregnancy planning |
Rubella IgG • Varicella IgG |
Follow timing per clinician |
How the Testing Process Works
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Match your checklist: pick the exact titers or screens your program or clinician requests.
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Time your draw: for post-vaccine checks, test ≥3–4 weeks after the last dose. IGRAs do not require fasting.
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Visit a draw site: one blood draw; some tests use additional tubes or same-day processing.
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Review results: compare to your report’s reference ranges and program criteria; your clinician may add imaging or confirmatory tests if indicated.
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Plan follow-up: vaccination, booster, or repeat testing may be advised for nonreactive or indeterminate results.
Interpreting Results (General Guidance)
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Titers (IgG): Reactive/positive suggests immunity; nonreactive/negative may reflect no immunity, early testing, or waning antibodies.
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COVID-19 antibodies: Spike+ / N− aligns with vaccination; Spike+ / N+ suggests prior infection; both negativecan mean no exposure or early/waning response.
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TB IGRAs: Positive indicates TB infection (latent or active) and needs clinical evaluation, often with chest X-ray; indeterminate often requires repeat or alternate IGRA.
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Immunoglobulins/subclasses: low levels or poor vaccine responses can suggest immune deficits; high polyclonal levels may reflect inflammation.
Always interpret results with a qualified healthcare professional; patterns, timing, and context matter more than a single value.
Choosing Panels vs. Individual Tests
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Program bundle: select a titer package (MMR, varicella, hepatitis B, tetanus/diphtheria) that mirrors your form.
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Single-question check: order one marker (e.g., anti-HBs after vaccination).
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Immune-function screen: IgG/IgA/IgM + CBC with differential, and add subclasses, pneumococcal serotypes, lymphocyte subsets, or complement based on findings.
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TB pathway: choose a single IGRA (QuantiFERON or T-SPOT) rather than TST when possible.
FAQs
Do I need to fast for these tests?
No. Titers, IGRAs, and immunoglobulins do not require fasting.
How soon after a vaccine should I draw a titer?
Wait at least 3–4 weeks after the final dose for the clearest result.
Will BCG affect my TB test?
BCG does not affect IGRA blood tests; it can affect the skin test (TST).
Can titers prove I’m fully protected?
Titers correlate with protection, but no test guarantees immunity for every disease. Follow your program rules and clinician advice.
What if my TB IGRA is positive?
You’ll need a clinician evaluation, usually a chest X-ray, and possibly sputum testing to rule out active disease.
My hepatitis B titer is negative—now what?
Your clinician may recommend a booster or repeat series and a follow-up titer.
Do recurrent infections mean immune deficiency?
Not always. Baseline Ig levels, CBC, and functional antibody tests help clarify next steps.
Related Categories & Key Tests
References
Available Tests & Panels
Your All Immunity and Titer Tests menu is pre-populated in the Ulta Lab Tests system. Use filters to build your package—required titers, COVID-19 antibodies, TB blood tests, and immune-function screens—and schedule your draw. Follow timing guidance (especially ≥3–4 weeks post-vaccination) and review results with your clinician before submitting documentation or planning next steps.
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