Fourth quarter 2024. The Lab Medicine Update is a collaboration between the UVA Medical Laboratories and the UVA Medical Laboratory Committee. Feedback on the LMU? Contact Jim Harrison (james.harrison@virginia.edu).
Discontinuation of In-house Fragile X Testing ↑
The UVA Clinical Genomics Laboratory will no longer offer in-house Fragile X testing. Fragile X testing can be performed by Mayo Medical Laboratories, using test code FXS, which is an orderable test in EPIC.
Addition to Benzodiazepine Confirmation Testing on Urine ↑
The Toxicology Laboratory has added alpha hydroxymidazolam, a midazolam metabolite, to the urine drug confirmation for benzodiazepines. Any result ≥ 25 ng/mL is considered positive and is reflective of midazolam use. This change was effective on September 26, 2024.
Change to Thyroglobulin Antibody Test Lower Reporting Limit ↑
The Thyroglobulin Antibody test [LAB515] lower reporting limit changed from 10 IU/mL to 15 IU/mL on 10/25/24. This change is is occuring because of a reagent reformulation that will reduce the potential for biotin interference and yield more accurate test results in patients taking biotin supplements.
Serum Free Light Chains Update to Instructions For Use ↑
Serum free light chains (kappa and lambda light chains) are measured in the UVA Medical Laboratory by turbidimetry. Turbidimetric methods may yield false low readings when there is substantial antigen excess (i.e., very high light chain levels; this is sometimes called a "high dose hook" effect). The method we use includes automatic checks for excess antigen levels and we have not seen an example of false low readings for this reason. However, no automated check will identify all cases of antigen excess and a very small percentage of samples with antigen excess may appear normal to the checks. The vendor of the method has updated the test instructions to include the following statement: “If these free light chain results do not agree with other clinical or laboratory findings, or if the sample is from a patient that has previously demonstrated antigen excess, the result must be checked by retesting at a higher sample dilution.” There is no change to the test itself. Patient results should always be interpreted in conjunction with other laboratory tests and clinical evidence; any anomalies should be discussed with the testing laboratory.
The Medical Laboratory Committee Seeks Clinician Members ↑
The Medical Laboratory Committee (formerly the Laboratory Stewardship Subcommittee) advises the UVA Medical Laboratory and the UVA Health System on a variety of medical laboratory topics, including the orderable test menu, available send-out tests, laboratory-related policies, and laboratory operational issues. The committee is co-chaired by a clinician and a laboratorian, and its membership includes about half patient-care clinicians and half laboratorians. In addition to influencing policy and operations, the Committee provides a forum for cooperative communication, discussion, and prioritization of a variety of topics related to operation and use of the lab. The Committee and the UVA Medical Lab encourage clinicians with interests in the optimal organization and use of the lab to join the Committee and contribute your enthusiasm and expertise. Contact the co-chairs Jim Harrison (jhh5y@uvahealth.org) and/or George Hoke (gmh4s@uvahealth.org) for more information.