Clinical Chemistry Podcast

Studies have found that drugs are now so prevalent that over 10% of a population were found to have traces of Class A drugs on their fingerprints despite never using any of those drugs.  While fingerprints have been suggested as a possible sample to rapidly and noninvasively carry out drug testing, identifying drug users and not those who may have passively encountered a drug can be complex. In a study published in the June 2018 issue of Clinical Chemistry and available online now, researchers from the University of Surrey together with Dutch scientists may have found a solution.  They present evidence that their techniques give a zero false positive rate in the fingerprints from drug-free volunteers.  Yet, they were able to detect 87.5% of the cocaine users and 100% of heroin users.

Familial hypercholesterolemia is a frequent genetic disorder encountered in clinical practice and is associated with high levels of serum LDL cholesterol known as the “bad cholesterol.” A diagnosis of familial hypercholesterolemia has important clinical implications with respect to risk of cardiovascular disease and a requirement for intensive pharmacological therapy. Often, the baseline LDL cholesterol before treatment is not available because the patient has initiated and continues on lipid lowering therapy, especially statins. Furthermore, the original baseline LDL cholesterol may predate the current status by many years and cannot be easily retrieved. The February 2018 issue of Clinical Chemistry published a paper describing a method to obtain an imputed, or estimated, baseline LDL cholesterol concentration in these patients who are already taking cholesterol lowering drugs. Both a computer program and a smartphone app are available from links in the paper. We are pleased to have the lead author of that p

A paper in the March 2018 issue of Clinical Chemistry describes a liquid chromatography tandem mass spectrometry procedure for multi-steroid profiling in Cushing syndrome and other disorders.  The lead author of that study is Dr. Graeme Eisenhofer, who is professor and the Chief of the Division of Clinical Neurochemistry at the Institute for Clinical Chemistry and Laboratory Medicine at the Technical University in Dresden, Germany.  He is our guest in this podcast.

Commutability is an important concept in determining traceability and the relationship among different methods that are used to measure the same analyte but just how to describe and classify commutable materials is not always straightforward.  The March 2018 issue of Clinical Chemistry published a series of three reports from the Working Group on Commutability of the International Federation of Clinical Chemistry and Laboratory Medicine, or IFCC, that describe recommendations for assessing commutability.

Normal pregnancy is associated with profound hormonal and metabolic changes in the mother, including changes in thyroid hormones.  These normal changes include increased thyroid binding globulin, increased total T3 and total T4, transient decrease in TSH, and in some patients, a transient increase in serum FT4 during the first trimester. In 2017, the American Thyroid Association issued new guidelines for the diagnosis and management of thyroid diseases during pregnancy, which can be difficult due to the numerous normal physiological changes.  Most would agree that the document is an excellent review of current literature relating to the assessment of thyroid status during pregnancy.  However, one researcher wonders if a particular recommendation of the document is misguided.