Use of Cotton Balls in Diapers for Collection of Urine Samples Impacts the Analysis of Routine Chemistry Tests: An Evaluation of Cotton Balls, Diapers, and Chemistry Analyzers.

Objective: To evaluate the suitability of urine samples collected with cotton balls placed into diapers for routine laboratory chemistry analyses.

Study Design: Twenty pools of residual unpreserved urine samples were separated into control and treated aliquots. The treated samples were absorbed into 2 different brands of cotton balls, wrapped in 3 different brands of diapers, and incubated at 37°C for 1 hour.

The 2021 PhD Board-Certified Clinical Chemist Compensation Survey.

Introduction: Doctoral-level clinical chemists work in various settings including academia, healthcare systems, reference laboratories, and industry. Information regarding compensation and benefits for PhD board-certified clinical chemists is limited. The American Association for Clinical Chemistry's (AACC) Society for Young Clinical Laboratorians (SYCL) Core Committee completed a compensation survey in February 2021 and compared that to previous survey results.

The 2018 AACC/SYCL PhD Clinical Chemist Compensation Survey.

Background: Doctoral level board-certified clinical chemists play an invaluable role in many facets of laboratory medicine and healthcare. However, information concerning their total compensation is sparse.

Content: A confidential self-reported compensation survey was conducted by the American Association for Clinical Chemistry's Society for Young Clinical Laboratorians (AACC SYCL) Core Committee from April 1 to April 17, 2018.

Unrecognized Elevations of Toxic Elements in Urine and Blood Highlight the Potential Need for a Broader Approach to Exposure Assessment.

Heavy metals testing remains an ongoing challenge for diagnosing acute or chronic exposure to heavy metals. In this study, we determined the positivity rates of single element and panel testing for toxic elements, and evaluated the potential utility of an expanded detection protocol for screening of toxic element exposures. The retrospective analysis included data from urine (n = 19,343) and blood (n = 196,019) specimens tested using inductively coupled plasma-mass spectrometry (ICP-MS) for arsenic, cadmium, lead and mercury (blood), and arsenic, cadmium, copper, lead, mercury and zinc (urine).

Reference Intervals for Intestinal Disaccharidase Activities Determined from a Non-Reference Population.

Background: Cutoff activities for diagnosing disaccharidase deficiencies are historical and are difficult to verify from a reference population. The objectives of this study were to validate the utility of historical disaccharidase cutoffs using data from clinical samples and to evaluate the demographics of individuals for whom intestinal disaccharidase testing was performed.

Methods: Results from 14,827 disaccharidase test samples were extracted from the laboratory information system.

Pathology consultation on urine compliance testing and drug abuse screening.

Objectives: Compliance testing in pain management requires a distinct approach compared with classic clinical toxicology testing. Differences in the patient populations and clinical expectations require modifications to established reporting cutoffs, assay performance expectations, and critical review of how best to apply the available testing methods. Although other approaches to testing are emerging, immunoassay screening followed by mass spectrometry confirmation remains the most common testing workflow for pain management compliance and drug abuse testing.

Total arsenic screening prior to fractionation enhances clinical utility and test utilization in the assessment of arsenic toxicity.

Objectives: The objective was to evaluate the utility of a screen with reflex-to-fractionation testing compared with direct-to-fractionation testing for suspected toxic exposure.

Methods: This study was based on a retrospective data analysis of urine arsenic results from previously tested samples (n=12,960). Total urine arsenic by inductively coupled plasma mass spectrometry was used as a screening method to identify elevated arsenic concentrations.

THE SYNTHESIS OF C-N-LABELED 3,5-DIIODOTHYRONINE AND THYROXINE.

Thyroid hormones undergo extensive metabolism to regulate hormone activity. A labeled thyroid hormone would be useful to track hormone metabolism through various pathways. While radiolabeled thyroid hormones have been synthesized and used for in vivo studies, a stable isotope labeled form of thyroid hormone is required for studying thyroid hormone metabolism by LC-MS/MS, an analytical technique that has certain advantages without the complications of radioactivity.

Biosynthesis of 3-iodothyronamine (T1AM) is dependent on the sodium-iodide symporter and thyroperoxidase but does not involve extrathyroidal metabolism of T4.

3-Iodothyronamine (T(1)AM) is an endogenous thyroid hormone derivative with unknown biosynthetic origins. Structural similarities have led to the hypothesis that T(1)AM is an extrathyroidal metabolite of T(4). This study uses an isotope-labeled T(4) [heavy-T(4) (H-T(4))] that can be distinguished from endogenous T(4) by mass spectrometry, which allows metabolites to be identified based on the presence of this unique isotope signature.

Identification and quantification of 3-iodothyronamine metabolites in mouse serum using liquid chromatography-tandem mass spectrometry.

3-Iodothyronamine (T(1)AM) is an endogenous derivative of thyroxine. Recently there have been numerous reports of analytical methods to quantify endogenous T(1)AM levels, but substantial discrepancies in concentration depending on the method of analysis (LC-MS/MS or immunoassay) suggest endogenous T(1)AM may be covalently modified in vivo. Using information dependent acquisition methods to perform unbiased scans for T(1)AM metabolites following a single IP injection in mice, we have identified O-sulfonate-T(1)AM, N-acetyl-T(1)AM and T(1)AM-glucuronide as conjugates occurring in vivo, as well as the oxidatively deaminated 3-iodothyroacetic acid and non-iodinated thyroacetic acid.

Validation of a liquid chromatography-tandem mass spectrometry method to enable quantification of 3-iodothyronamine from serum.

There is great interest lately in the availability of analytical methods for quantification of 3-iodothyronamine from blood and tissues. To date, no validated method for determination of 3-iodothyronamine from biological matrices has been described. Detailed in this report is an LC-MS/MS method that permits accurate and reproducible quantification of pharmacological concentrations of 3-iodothyronamine from rat serum, with a 0.