6-Thioguanine Nucleotides
Private 6-Thioguanine Nucleotides blood test in London for £407, measuring one thiopurine metabolite marker with results in around 2 weeks.
Turnaround time
2 weeks
Biomarkers count
1
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Overview of the 6-Thioguanine Nucleotides
The 6-Thioguanine Nucleotides blood test is a specialist therapeutic drug-monitoring investigation that measures 6-TGN, a group of active metabolites produced when the body processes thiopurine medicines.
Thiopurine medicines include azathioprine, mercaptopurine and thioguanine. They are used in the management of several inflammatory, autoimmune and haematological conditions and are particularly well established in inflammatory bowel disease, including Crohn's disease and ulcerative colitis.
People can metabolise the same prescribed dose differently. Measuring the prescribed dose alone therefore does not show how much active thiopurine metabolite is present within the body.
The test contains 1 biomarker: 6-Thioguanine Nucleotides. Measuring 6-TGN within red blood cells can provide additional information about exposure to active thiopurine metabolites.
Testing may support investigation of inadequate treatment response, unusually high metabolite exposure, medication adherence or dose optimisation.
6-TGN testing does not replace routine Full Blood Count or liver-function monitoring, and treatment doses should not be changed solely on the basis of one metabolite result without review by the prescribing clinician.
What Does the 6-Thioguanine Nucleotides Test Check?
This test measures 1 biomarker.
6-Thioguanine Nucleotides
Measures active thiopurine metabolites within red blood cells. The result can provide information about exposure to medicines including azathioprine, mercaptopurine and thioguanine and may support assessment of treatment response, adherence and possible excessive metabolite exposure.
Who May Benefit From the 6-Thioguanine Nucleotides Test?
This test may be suitable for people already receiving thiopurine medication who require therapeutic drug monitoring as part of their ongoing clinical care.
People taking azathioprine - 6-TGN measurement can help assess how effectively azathioprine is being converted into active metabolites.
People taking mercaptopurine - Testing may provide additional information when treatment response or dosage is being reviewed.
People taking thioguanine - Monitoring may be requested by a specialist during treatment.
Crohn's disease treated with thiopurines - Metabolite monitoring may be useful where disease control is inadequate or treatment optimisation is being considered.
Ulcerative colitis treated with thiopurines - 6-TGN testing may help clinicians assess medication exposure where treatment response is not as expected.
Possible treatment-related side effects - A clinician may request metabolite testing alongside Full Blood Count, liver-function tests and other safety investigations.
Unexpected lack of treatment response - Low or otherwise unexpected metabolite concentrations can provide additional information when prescribed treatment appears ineffective.
Thiopurine dose review - Testing may be requested following a clinically significant dose change or once treatment has reached a stable regimen.
Assessment of medication adherence - Unexpectedly low metabolite exposure may contribute to the wider assessment of whether medication is being taken consistently.
How to Prepare
Do not stop, skip, increase or reduce your thiopurine medication simply to alter a 6-TGN result unless specifically instructed by the clinician responsible for your treatment.
Providing your prescribed dose, recent dose changes and previous monitoring results can be particularly useful because 6-TGN is interpreted as part of ongoing therapeutic drug monitoring rather than in isolation.
Symptoms and Reasons to Consider the 6-Thioguanine Nucleotides Test
You may wish to consider the 6-Thioguanine Nucleotides test when thiopurine treatment is not producing the expected clinical response, when adverse effects are being investigated or when a specialist requires additional information about medication exposure.
Poor control of the underlying condition - Persistent or returning symptoms despite thiopurine treatment may prompt assessment of active metabolite exposure.
Disease flare despite treatment - Recurrence of Crohn's disease, ulcerative colitis or another condition being treated with a thiopurine may lead to therapeutic drug monitoring.
Unexpected changes in blood counts - Reduced white cells, platelets or other blood-count abnormalities require appropriate clinical assessment during thiopurine therapy.
Abnormal liver blood tests - Changes in liver enzymes during thiopurine treatment may prompt additional safety and metabolite monitoring.
Frequent infections - Increased susceptibility to infection during immunosuppressive treatment should be medically assessed.
Unexplained fatigue or weakness during treatment - These symptoms are non-specific but may occur alongside blood-count abnormalities or other treatment-related effects.
Dose adjustment or treatment optimisation - Testing may be requested even when no symptoms are present if a specialist wants additional information before reviewing therapy.
Symptoms occurring during thiopurine treatment should not automatically be attributed to medication. Infection, inflammatory disease activity and other medical conditions can produce similar symptoms.
6-TGN results should be interpreted together with the prescribed dose, treatment adherence, clinical response, Full Blood Count and liver-function results.
Severe infection, significant bleeding, jaundice, persistent fever or rapidly worsening symptoms require prompt medical assessment rather than waiting for routine metabolite results.
How to Book Your 6-Thioguanine Nucleotides Test
Booking your 6-Thioguanine Nucleotides test with London Blood Tests is simple and designed to fit around your schedule.
Choose the 6-Thioguanine Nucleotides
Select the 6-Thioguanine Nucleotides test online and review the included thiopurine metabolite biomarker before booking.
Select your sample collection option
Choose an in-clinic blood draw (+£35) or a home or hotel phlebotomy visit (+£60) where a qualified phlebotomist collects your sample.
Attend your appointment
A trained professional will collect your blood sample safely and efficiently at the clinic or during your arranged home or hotel visit.
Laboratory analysis
Your sample is sent to the laboratory, where 6-Thioguanine Nucleotides are measured using specialist therapeutic drug-monitoring analysis.
Receive your results securely
Your results are sent securely by email, ready to review yourself or discuss with your gastroenterologist, haematologist, rheumatologist, GP or other prescribing clinician.
When Will I Receive My Results?
The expected turnaround time for the 6-Thioguanine Nucleotides test is approximately 2 weeks after your sample arrives at the laboratory.
Results are sent securely by email once specialist laboratory analysis and authorisation are complete. Turnaround therefore begins when the laboratory receives the sample rather than necessarily from the time your blood is collected.
Specialist therapeutic drug monitoring may occasionally require repeat analysis, confirmation or additional laboratory review, which can extend the expected turnaround.
Understanding Your Results
Your 6-Thioguanine Nucleotides result shows the measured concentration of active thiopurine metabolites according to the laboratory method and interpretative criteria used.
A lower 6-TGN concentration may indicate relatively low exposure to active thiopurine metabolites. Possible explanations can include the prescribed dose, individual metabolism, recent treatment changes or inconsistent medication use.
A result within the laboratory's expected therapeutic interval may indicate exposure considered compatible with treatment in the relevant clinical setting, although it does not guarantee that the underlying condition will be adequately controlled.
Higher 6-TGN concentrations can be associated with an increased risk of thiopurine-related bone marrow toxicity, including suppression of blood-cell production.
Therapeutic targets are not necessarily identical for every condition or laboratory method. Results should therefore be interpreted using the information supplied by the analysing laboratory.
6-TGN measurement does not provide a complete assessment of thiopurine safety and does not replace routine Full Blood Count or liver-function monitoring.
Do not increase, reduce or stop azathioprine, mercaptopurine, thioguanine or another prescribed medicine solely on the basis of your laboratory result.
Why Book With London Blood Tests?
Private thiopurine monitoring in London - Access specialist 6-TGN therapeutic drug monitoring through London Blood Tests.
Targeted active metabolite measurement - Measure 6-Thioguanine Nucleotides without having to book a broad general health profile.
Relevant to azathioprine monitoring - 6-TGN can provide additional information about exposure to active metabolites during azathioprine treatment.
Relevant to mercaptopurine and thioguanine monitoring - Testing can also support assessment of other commonly used thiopurine medicines.
Useful when treatment response is inadequate - Metabolite measurement may help clinicians investigate unexpected loss of response or inadequate disease control.
Specialist laboratory analysis - Your sample is processed using dedicated therapeutic drug-monitoring methods.
Clinic and home visit options - Choose an in-clinic blood draw or arrange home or hotel phlebotomy depending on location and availability.
Secure results by email - Receive your authorised laboratory result securely once analysis is complete.
Clear pricing before booking - The 6-Thioguanine Nucleotides test is priced at £407, with sample collection charges shown separately.
Private 6-Thioguanine Nucleotides Blood Test in London
London Blood Tests provides the 6-Thioguanine Nucleotides blood test in London for people requiring specialist therapeutic drug monitoring while taking thiopurine medication.
The test costs £407 and measures one biomarker: 6-Thioguanine Nucleotides. These active metabolites are produced when the body processes medicines such as azathioprine, mercaptopurine and thioguanine.
Clinic appointments are available alongside home and hotel phlebotomy depending on location and availability, providing flexible options for people looking for private 6-TGN testing in London or specialist thiopurine monitoring near them.
A 6-TGN result should not be interpreted independently. The prescribing clinician may also consider the medication dose, clinical response, Full Blood Count, liver-function results and other relevant monitoring information.