What is 6-TGN blood test?
What is 6-TGN blood test?
6-thioguanine nucleotides (6-TGNs) are the active metabolites of the cytotoxic drugs Azathioprine, Mercaptopurine and Thioguanine. Measurement of 6-TGNs helps to confirm therapeutic concentrations and to avoid toxicity.
What does low thiopurine metabolites mean?
Collapse Section. 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 is a thiopurine metabolites test?
This test is primarily used to verify compliance, optimize therapy, and identify elevated metabolite concentrations that may result in toxicity after initiation of thiopurine drug therapy for the treatment of inflammatory bowel disease.
What is thiopurine toxicity?
Thiopurines present toxicity at distinct levels: myelosuppression, hepatotoxicity, pancreatitis and gastrointestinal intolerance, among others. Toxicity is an important cause of treatment cessation; in IBD, about 15% of patients discontinue thiopurines due to adverse events [4,5].
What is a normal TPMT level?
Normal TPMT activity: 25-65 U/mL – Individuals are predicted to be at low risk of bone marrow toxicity as a consequence of standard thiopurine therapy; no dose adjustment is recommended.
What is 6-mercaptopurine used for?
MERCAPTOPURINE, 6-MP (mer kap toe PYOOR een) is a chemotherapy drug. It interferes with the growth of cancer cells and can reduce immune system activity. It is used to treat certain types of acute leukemia.
What are thiopurine metabolites?
Thiopurines (azathioprine and mercaptopurine) are one of the immunosuppressive mainstays for the treatment of inflammatory bowel disease. In spite of its widespread use, thiopurine metabolism is still not fully understood, and a significant proportion of patients suffer toxicity or lack of efficacy.
What does high TPMT 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.
Why is TPMT test done?
Why is TPMT Testing Important? Detection of individuals with low thiopurine methyltransferase (TPMT) activity who are at risk for excessive myelosuppression or severe hematopoietic toxicity when taking thiopurine drugs.
What drugs are thiopurines?
MN There are 3 types of thiopurines that have been used for inflammatory bowel disease (IBD) therapy: azathioprine, 6-mercaptopurine, and thioguanine. The first 2 are approved for the treatment of IBD, and the third has been tested in clinical trials.
What causes low thiopurine methyltransferase?
Health Conditions Related to Genetic Changes Changes in the TPMT gene cause TPMT deficiency, which is a reduction in the activity of the TPMT enzyme. Without enough of this enzyme, the body cannot “turn off” thiopurine drugs by metabolizing them into inactive compounds.
What is the blood test for azathioprine?
Before prescribing azathioprine, your doctor will order a blood test for an enzyme called TPMT, also known as thiopurine methyltransferase (thio-pew-reen meth-ile-trans-fe-raise). Enzymes are proteins in your body that can help to break down certain substances or chemicals.