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ConA Response

Immunology & Autoimmune

ConAConcanavalin A lymphocyte proliferation

Review status

Currently under review

Pending specialist review and validation.

What it shows

The ConA Response is a functional immune test that looks at how your T lymphocytes respond when stimulated with concanavalin A, a plant lectin commonly used as a mitogen. In simple terms, it assesses how well a key part of your immune system can become activated and proliferate in the lab when given a strong trigger.

This test is performed on a fresh blood sample. The laboratory isolates or cultures your white blood cells and exposes them to concanavalin A, then measures the overall level of response. Results are typically expressed as a response level relative to cells that were not stimulated.

Why it matters

T cells are central to fighting certain infections and coordinating many immune functions. If their response is weak, you may be more prone to specific infections or have difficulty clearing them. Clinicians use the ConA Response to evaluate cellular immune function in people with recurrent or unusual infections, to monitor the impact of immunosuppressive treatment, after transplant, or during follow up for conditions that can affect T cells.

Understanding your ConA Response can help your care team decide on next steps, such as adjusting medications, ordering additional immune tests, or planning vaccinations. The test itself involves drawing blood, and while risks are minimal, the sample must be handled promptly because living cells are being evaluated.

Understanding your results

A lower than expected response can point to reduced T cell function, which can be due to primary immune disorders, immunosuppressive drugs, recent severe illness, or effects from treatments like chemotherapy. A robust response suggests that your T cells are capable of activating under strong stimulation. Results are interpreted alongside your symptoms, exam findings, blood counts, lymphocyte subsets, and responses to other mitogens or antigens.

If your result is unexpected, your clinician may repeat the test, especially if there were possible preanalytic issues such as delayed transport or suboptimal temperature during shipping. Depending on your history, your care team may consider additional testing or referral to an immunology specialist to understand the cause and discuss management.

Reference ranges

1660 %
All sexes
0 days – 150 years

Reference intervals vary by laboratory, analyzer, methodology, population, and units. The ranges shown here are for education only. Always interpret your results against the reference interval printed on your own lab report.

Factors that could impact ConA Response

  • Specimen timing and temperature

    T cell function declines if blood is not processed quickly or if it is exposed to temperatures outside room temperature ranges. Prompt collection, correct anticoagulant, and rapid transport help ensure reliable results.

  • Immunosuppressive medications

    Corticosteroids, calcineurin inhibitors, mTOR inhibitors, antimetabolites, biologics, and chemotherapy can blunt lymphocyte responses. Tell your clinician about all medicines and supplements you are taking.

  • Recent infections or vaccines

    Acute infections, febrile illness, and recent vaccinations can temporarily alter lymphocyte activation. Your provider may time testing to avoid periods of acute illness when feasible.

  • Age and comorbid conditions

    Very young or older individuals, and people with chronic illnesses such as kidney or liver disease, diabetes, or malnutrition, may have altered T cell responses that influence interpretation.

  • Anticoagulant and collection tube

    The assay typically requires heparinized whole blood. Using the wrong tube or clotted specimens can invalidate the test by reducing viable lymphocytes.

  • Transport delays and shipping

    Extended transport times or weekend shipping can reduce cell viability. Scheduling collection earlier in the week and coordinating courier pickup can prevent delays.

  • Pregnancy

    Physiologic immune adaptations during pregnancy can modulate cellular responses. Your clinician will interpret results in the context of pregnancy status.

2026

References

  1. McGill University Health Centre. (2021, June 07). ConA Response (Task CD 23030938). Laboratory reference ranges.
  2. Bonilla, F. A., Khan, D. A., Ballas, Z. K., Chinen, J., Frank, M. M., Hsu, J. T., Keller, M., Kobrynski, L., Komarow, H. D., Levy, O., Milner, J. D., Pettersen, E. F., Puck, J. M., Secord, E., Shapiro, R. S., Verbsky, J. W., & Shearer, W. T. (2015). Practice parameter for the diagnosis and management of primary immunodeficiency. Journal of Allergy and Clinical Immunology, 136(5), 1186–1205. External link