What is Prometheus TPMT enzyme test?

​PROMETHEUS TPMT Enzyme testing provides a quantitative analysis of a patient’s thiopurine methyltransferase (TPMT) enzyme activity level. Because each patient metabolizes thiopurines differently, the efficacy and toxicity of thiopurines can vary widely from patient to patient.

What is normal TPMT level?

Normal TPMT activity: 24.0-44.0 U/mL – Individuals are predicted to be at low risk of bone marrow toxicity (myelosuppression) as a consequence of standard thiopurine therapy; no dose adjustment is recommended.

Should we test TPMT enzyme levels before starting azathioprine?

A further 10% of people have lower than normal TPMT and are likelier than people with normal activity to develop bone marrow suppression. Testing TPMT activity before starting azathioprine can identify people who are TPMT deficient and who should not receive the drug.

What should be checked before starting azathioprine?

Regular blood tests during treatment Taking azathioprine can sometimes affect your liver, kidneys or bone marrow. You will have blood tests to check your liver function, kidney function and blood count before you start taking this medicine.

What is the TPMT enzyme blood test for?

TPMT genetic test (genotype)—an alternative test to TPMT enzyme activity level is a genetic test that can identify genetic variations in the TPMT gene. This genetic test identifies individual genetic differences associated with risk for thiopurine toxicity. Each person has two copies of the TPMT gene.

How much does the Prometheus blood test cost?

test coverage† Your out-of-pocket cost is capped at $250. If you are eligible* for the PROMETHEUS Links Program, $250 may be further reduced to $175 or $75.

What is a low TPMT level?

If someone’s TPMT activity is too low, the person may not effectively metabolize thiopurines, which can lead to severe side effects. About one person in every 300 is severely deficient in TPMT, and about 10% of the population in the U.S. has lower than normal levels of TPMT.

What is TPMT deficiency?

Thiopurine S-methyltransferase (TPMT) deficiency is a condition characterized by significantly reduced activity of an enzyme that helps the body process drugs called thiopurines. These drugs, which include 6-thioguanine, 6-mercaptopurine, and azathioprine, inhibit (suppress) the body’s immune system.

What does a low TPMT level mean?

Complete TPMT deficiency (TPMT <10 nmol/h/g Hb) indicates that there is an absolute intolerance to thiopurine drugs. Low activity indicates partial enzyme deficiency and therefore that the probability of azathioprine-induced bone marrow depression or nausea is HIGH.

What causes low TPMT?

TPMT deficiency results from changes in the TPMT gene. This gene provides instructions for making the TPMT enzyme, which plays a critical role in breaking down (metabolizing) thiopurine drugs. Once inside the body, these drugs are converted to toxic compounds that kill immune system cells in the bone marrow.