Automation of the Whole-Blood Thiopurine -Methyltransferase (TPMT) Phenotyping Assay Using the Biomek NX and Biomek i5 Liquid-Handling Workstations.

Assessment of thiopurine -methyltransferase (TPMT) status is required before commencing thiopurine treatment to reduce the potential for adverse drug reactions. Our laboratory has provided a national TPMT phenotyping service since 2003. Our assay uses 6-thioguanine as substrate and detection of 6-methylthioguanine via high-performance liquid chromatography (HPLC) fluorescence.

Analytical evidence to show letters impregnated with novel psychoactive substances are a means of getting drugs to inmates within the UK prison service.

Introduction Novel psychotropic substances also known as legal highs are a major concern in UK prisons, fuelling violence and putting a strain on resources for inmates requiring medical treatment for adverse effects. We provide a clinical toxicology service including routine screening for novel psychoactive substances. In 2015, we were approached by Her Majesty Prison Service search dog training team to advise on which novel psychoactive substances to target, and again in 2016 to further provide analytical support to test five letters which the dogs positively identified for novel psychotropic substances during routine searches of prison mail rooms.

Self-administration of vitamin D supplements in the general public may be associated with high 25-hydroxyvitamin D concentrations.

Introduction Our dried blood spot vitamin D testing service enables members of the public to assess their vitamin D status. Vitamin D has become popular with the media and the general public. We noticed that our direct access service had a higher rate of high to toxic 25-hydroxyvitamin D levels compared with our GP population and we wanted to know why.

Analysis of legal high materials by ultra-performance liquid chromatography with time of flight mass spectrometry as part of a toxicology vigilance system: what are the most popular novel psychoactive substances in the UK?

Introduction Legal highs also known as novel psychoactive substances mimic the effects of classic drugs of abuse. Challenges to developing screening services for novel psychoactive substances include identifying which novel psychoactive substances are available to target. Using new techniques such as exact mass time of flight can help identify common novel psychoactive substances to target for screening patient samples by routine methods such as tandem mass spectrometry.

1-Adamantylamine a simple urine marker for screening for third generation adamantyl-type synthetic cannabinoids by ultra-performance liquid chromatography tandem mass spectrometry.

Background Synthetic cannabinoids (NOIDS) are novel psychotropic drugs (NPS) currently freely sold in the United Kingdom as 'research chemicals'. Detection of NOIDS use is not available in current routine methods. Here we describe a marker which helps determine which patients have used these substances.

Five-year review of a UK 24 hour testing service for plasma ethylene glycol and diethylene glycol.

Background: We present a 5-year review of our UK service for plasma ethylene glycol and diethylene glycol determination in cases of acute poisoning.

Methods: Ethylene glycol and diethylene glycol have been measured on all samples received for screening for toxicity by gas chromatography-flame ionization detection over a five-year period. A detailed audit of the results has been undertaken.

Serum trough infliximab and anti-infliximab antibodies in a cohort of gastroenterology and rheumatology patients' infliximab therapeutic drug monitoring.

Background: Infliximab, a monoclonal antibody directed against tumour necrosis factor, is widely used in the treatment of chronic inflammatory conditions including Crohn's disease and rheumatoid arthritis. Its use is limited by development of anti-infliximab antibodies, which can lead to loss of therapeutic efficacy. Serum infliximab and anti-infliximab antibody measurements have recently become routinely available in the UK.

Ethnic variation of thiopurine S-methyltransferase activity: a large, prospective population study.

Unlabelled: The use of azathioprine (and its metabolite mercaptopurine) is limited by toxicity, especially myelosuppression, which is related to activity of the enzyme thiopurine S-methyltransferase (TPMT). TPMT activity varies between individuals and is considered deficient in one in 300 cases.

Aims & Methods: We identified TPMT activity within an ethnically diverse population of patients attending an inner-city hospital phlebotomy service.

Reference intervals for thiopurine S-methyltransferase activity in red blood cells using 6-thioguanine as substrate and rapid non-extraction liquid chromatography.

Background: Although widely used, thiopurine drugs have a narrow therapeutic index and treatment can result in life-threatening toxicity, the basis being pharmacogenetic variation in thiopurine metabolism by thiopurine S-methyltransferase (TPMT). We recently developed a modified phenotyping assay to determine TPMT activity in red blood cells. Here we describe improvements to the method and establish reference intervals in a large prospective study.

Determination of thiopurine S-methyltransferase activity in erythrocytes using 6-thioguanine as substrate and a non-extraction liquid chromatographic technique.

A non-extraction high-performance liquid chromatographic (HPLC) method has been developed for the determination of 6-methylthioguanine (6-MTG), as part of the determination of thiopurine S-methyltransferase activity (TPMT) in erythrocytes. Erythrocyte lysate is added to a glass vial containing substrates and incubation buffer, which is then sealed for the rest of the analysis. Enzyme incubation, sample preparation, and analysis are then undertaken without further sample-handling steps.