Deceptively Simple: Can Urine Samples from CLIA-Waived Urine Drug Screen Devices Be Reused for Confirmatory Testing?

BACKGROUND: Many low-complexity urine drug screen (UDS) devices are approved by the Food and Drug Administration as waived under Clinical Laboratory Improvement Amendments (CLIA) criteria. Labeling instructs patients to urinate directly into the device and also states that positive results should be confirmed. However, the device itself may pose a risk of drug adsorption and/or specimen contamination that could affect results in confirmatory assays if specimens are reused. Collecting urine in a separate container before performing the UDS would reclassify the test as nonwaived, negating the conveniences of a CLIA-waived test. Also, patients may be unable or unwilling to urinate in an additional container for confirmatory testing. This study examined reusing urine from a UDS device (NexScreen) for confirmatory testing. METHODS: 25 patient specimens were pooled and verified to be drug-free. To evaluate drug leaching from the UDS device, 30 mL of this pool was incubated in NexScreen cups, followed by confirmatory testing. To evaluate drug adsorption, 14 representative analytes were spiked slightly over the NexScreen positivity cutoffs, followed by incubation in NexScreen cups and confirmation testing. RESULTS: All negative samples incubated in NexScreen cups remained negative upon confirmation testing, indicating that NexScreen test strips do not contaminate the specimen. For the drug adsorption experiment, 11 of 14 analytes had recoveries of at least 95%, whereas buprenorphine and 11-nor-9-carboxy-tetrahydrocannabinol recovered at 94% and 87%, respectively, suggesting minor adsorption. All analytes recovered above their respective confirmation cutoffs. CONCLUSIONS: Urine aliquots from NexScreen cups may be used for confirmatory testing.

Spirited away: Can ethanol testing in add-on orders provide meaningful results?

Ethanol is a volatile substance, and specimens need to be tightly capped prior to analysis to prevent evaporative loss. However, add-on requests in previously decapped tubes are commonly received, yet ethanol stability in this setting is unclear. We compared the stability of ethanol in capped vs decapped tubes in the context of routine laboratory automation, storage time, and specimen volumes. Serum specimens were pooled and spiked with ethanol followed by simulating an add-on scenario. Additionally, to evaluate ethanol stability at room temperature for extended times, ethanol concentrations were measured in capped or decapped tubes containing 0.5 mL or 0.1 mL samples over a 4 h time course. Finally, the risk of misclassification of ethanol results in decapped tubes was evaluated near the critical value threshold (∼54 mmol/L). The add-on tubes had a mean recovery of 101.5 % (95 % CI: 97.7-105.4 %) relative to the direct tubes. The time-course experiment showed an average recovery of 87.4 % (95 % CI: 81.8-94.0 %) at the 4 h time point in decapped 0.5 mL specimens. An average recovery of 85.4 % (95 % CI: 84.2-86.1 %) was observed for specimens spiked near the critical value threshold. Importantly, all measurements with 0.5 mL specimen volume were within 25 %, which is the total allowable error (TAE) of the assay.However, with a 0.1 mL volume, specimens cross the TAE threshold just after 1 h, and the percent recovery at 4 h dropped to 52.9 % (95 % CI: 50.2-55.7 %). In conclusion, ethanol testing in decapped tubes remains within the TAE for up to 4 h in specimens with a 0.5 mL volume. Therefore, add-on ethanol testing using routine laboratory automation and storage conditions can be successfully performed.

Molecular Diagnostic Advances in Transplant Infectious Diseases.

PURPOSE OF REVIEW: The infectious complications of transplantation can have devastating consequences for patients. Early and accurate diagnosis is essential to good outcomes. This review describes recent advances in pathogen-directed diagnostic testing and discusses the role of new methods for transplant infectious diseases. RECENT FINDINGS: Several molecular assays have been introduced into clinical practice in recent years. When the results of rapid testing are linked to patient-specific interventions, improved outcomes can be realized. Syndromic testing along with metagenomic next-generation sequencing (mNGS) represents novel approaches to infection diagnosis. However, the optimal use of these tests for transplant patients along with an overall assessment of cost-effectiveness demands further study. Molecular diagnostics are revolutionizing transplant care. Clinicians need to be aware of the current diagnostic landscape and have a working knowledge of the nuances related to test performance, result interpretation, and cost.

Pulmonary Mycobacterial Spindle Cell Pseudotumor: A Report of 3 Cases Including a Practical Approach to Histopathologic Recognition of This Unusual Entity.

Mycobacterial spindle cell pseudotumor (MSP) is a rare benign spindle cell lesion containing acid-fact mycobacteria. These lesions are most commonly identified in the lymph nodes, skin, spleen, or bone marrow of immunocompromised patients and only rarely involve the lungs. We report 3 cases of pulmonary MSP, which include 2 patients who are known to be HIV-positive. The histopathological diagnosis of MSP in the lung lends itself to many challenges due to its rare incidence and its spindled tumor-like appearance. The differential diagnosis is broad and includes both benign and malignant entities. We highlight the importance of the clinical context in which these lesions typically present and the morphologic spectrum of features seen, and we offer a practical approach to the workup of pulmonary mycobacterial pseudotumor. Appropriate recognition of this entity should lead to an accurate diagnosis of a treatable benign condition despite the clinical presentation often favoring malignancy.