MELISA measures immune response, so drugs that suppress this response may affect the results. T-cells specifically are used for testing.

Oral (systemic) use of immunosuppressants is the main concern as it may take weeks for T-cells to recover and be capable of an adequate cell response in MELISA.

In terms of T-cell suppression, there is a difference between oral (systemic) and nasal/topical (local) use, or inhaled steroids. Systemic T-cell function is generally preserved in such cases. Systemic absorption can occur, especially at high doses, prolonged use, and in children or the elderly.
Even if local or inhaled steroids cause some systemic T-cell suppression, recovery is faster than after systemic use. It is recommended to avoid such medication for a few days in case of high doses or long-term use.

In certain cases, where it is not possible to stop taking medication, we have incidences of patients with successful test results. It may be useful to send extra blood (1-2 tubes) to ensure that sufficient lymphocytes can be recovered. Please consult with the lab that should provide the test in advance. 

The following list of medications is not exhaustive, and patients should check with their health care professional to see if any of their current medication has an immune suppressant effect. Patients must speak with their healthcare professional before stopping any prescribed medication.

Systemic infection can significantly affect the results, primarily by modifying immune cell behaviour. T-cells may be in an activated or suppressed state, affecting their response to test antigens. This can lead to false-positive or false-negative results. Infection may lead to lymphocytopenia or impaired lymphocyte function, lowering test sensitivity.

Hemolysed samples may be unusable for MELISA. Samples of patients with high hematocrit are prone to hemolysis, as citrate tubes are used for blood collection. High hematocrit skews the blood-to-additive ratio in citrate tubes, which can destabilise cells and lead to hemolysis. In such a case, adjusting the amount of citrate in the tubes is recommended in order to proceed with blood draw for MELISA. This adjustment should be calculated, not guessed. This is recommended if HCT is >55%.

High hematocrit is a condition where the proportion of red blood cells in the blood is abnormally high. This primarily occurs in patients with Polycitemia vera. The condition can also be present in cases of increased erythropoietin or hypoxia-driven and should be considered in patients with erythropoietin-secreting tumors, chronic hypoxia and also in cases of testosterone therapy.

• Anti depressants
• Anti histamines
• THC – medical marijuana
• Finasteride
• NSAIDs

If a patient has a reduced white blood cell count, specifically a low lymphocyte count, we recommend sending 1 to 3 additional blood collection tubes, depending on the severity of the condition and the number of substances being tested.

This ensures that there is sufficient sample volume for accurate and reliable testing. A list of priority metals can also be included with samples to ensure the most important substances are not omitted.