March, 2023. The Lab Medicine Update is a collaboration between the UVA Medical Laboratories and the UVA Clinical Laboratory Stewardship Subcommittee. Feedback on the LMU? Contact Jim Harrison (james.harrison@virginia.edu).
Cystatin C testing moving in-house ↑
Cystatin C with eGFR testing [LAB6485], currently sent out to Mayo, will be moved in-house on 4/11/23. Measurement of Cystatin C will be performed on the Binding Site Optilite analyzer. Estimated GFR will be calculated using the Schwartz Cystatin C equation for pediatric (0-17) patients and the CKD-EPI Cystatin C (2012) equation for adult (>=18) patients. Cystatin C is used as an aid in the diagnosis and treatment of renal diseases. This test should be used in conjunction with other laboratory and clinical findings.
Specimen Requirements: 3 mL blood in a gold top (serum gel) tube is preferred, or 3 mL blood in red top tube can be used as an alternative. Processing details are available in the UVA Epic procedure catalog. The test will be performed Monday – Friday with a turnaround time of 3 days.
Resuming rapid identification of gram positive organisms in blood cultures ↑
An ongoing reagent shortage has limited the ability of the Microbiology Laboratory to perform rapid identification of gram positive organisms in blood cultures. The laboratory responded by validating a new rapid gram positive identification panel from a different vendor on an emergency basis. This new panel is now available and the laboratory will resume rapid reporting of gram positive organisms as part of the routine blood culture workflow. There are a few minor differences vs. the previous panel as noted below.
Organisms detected with this new panel include:
- Enterococcus faecalis (with or without vancomycin resistance)
- Enterococcus faecium (with or without vancomycin resistance)
- Streptococcus sp (those not listed below)
- Streptococcus pyogenes (Group A Strep)
- Streptococcus agalactiae (Group B Strep)
- Streptococcus pneumoniae
- Staphylococcus sp (those not listed below)
- Staphylococcus aureus (with or without methicillin resistance)
- Staphylococcus epidermidis
- Staphylococcus lugdunensis
Notable differences in reporting:
- Reporting from this panel is restricted to Gram positive cocci in chains and clusters (Staph, Strep, Enterococci).
- No Gram positive bacilli will be reported at this time.
- Streptococcus anginosus will not be identified as a separate organism identification, but will be detected as “Streptococcus sp” and cannot be differentiated from other organisms in this group.
Testing for gram negative organisms and yeast is not affected.
Lyme disease reflex testing update ↑
Effective April 11 Lyme disease testing will be performed in the UVA Core Laboratory following the updated CDC recommendations for two-tiered testing. Enzyme immunoassay (EIA) screening tests for total Lyme disease antibodies that are positive will reflex for confirmation to a second FDA-approved EIA that is specific for IgG and IgM antibodies. Western blots for Lyme disease will no longer be performed.
Gold top tubes no longer acceptable for ionized calcium ↑
Gold top tubes are no longer accepted for ionized calcium assay [Lab54] and this option has been removed from the Epic procedure catalog. The preferred sample is whole blood in a heparinized syringe, with whole blood in a light green top tube as an alternative. The specimen should not be centrifuged and is stable at room temperature for 30 min or on ice for 2 hours. This change is associated with a change in instrumentation for the test.
Amniotic fluid lamellar body testing discontinued ↑
The UVA Medical Laboratory has retired local amniotic fluied lamellar body testing because of low utilization and lack of inclusion in current clinical guidelines. The test remains available as a sendout to Mayo Laboratories, daily with a one day turnaround time. This decision was reviewed by the Medical Laboratory Stewardship Subcommittee and reported to the Patient Care Committee.
Nephrocheck testing discontinued ↑
Nephrocheck will be discontinued as an orderable test on March 24. The test attempts to predict the risk of developing acute kidney injury based on urine levels of insulin-like growth-factor binding protein 7 (IGFBP7) and tissue inhibitor of metalloproteinases (TIMP-2). It is being discontinued based on lack of clinical utility after review with the clinical staff.
Updates on Mayo sendout tests ↑
- Plasma Catecholamines [LAB870] specimen and collection procedure changes: Samples must be drawn from an indwelling catheter into a specific tube containing EDTA and Metabisulfite. Details are in the UVA Epic procedure catalogue.
- NT-Pro BNP: The test code has changed from PBNP (obsolete) to PBNP1. Serum gel tubes and red top tubes are both acceptable. Serum should be removed from cells within 2 hours of collection.
- Thyroglobulin, Tumor Marker, Fine-Needle Aspiration Biopsy Needle Wash: The test code is TFNAB, which replaces the obsolete HTGFN. Please include site location and lymph node or non-Lymph node source in the order. A separate order is required for each site biopsied.
- Salivary Cortisol, AKA "Midnight Cortisol": There is a new orderable test code, LAB6481, JSALCT in Epic. The test was previously ordered as a Miscellaneous Mayo non-genetic test. The samples are collected by the patient in test-specific salivette tubes. The tubes should be labelled with the collection date and time and 2 patient identifiers.