May, 2022. 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).
Cerebrospinal fluid flow cytometry with low WBC ↑
As of February 2022 flow cytometry orders on cerebrospinal fluids are no longer automatically canceled based on low white blood cell (WBC) count by manual CSF cell count. Flow cytometry orders placed on cerebrospinal fluid specimens will be performed as per the clinical flow cytometry laboratory procedure. Flow cytometry has a higher sensitivity than cell count and may detect a leukocyte population with a manual WBC count of 0. Please be aware and modify standing orders as needed.
Contact information:
Elizabeth Courville, MD
Medical Director, Clinical Flow Cytometry Laboratory
ec8kk@hscmail.mcc.virginia.edu
Updated race-free eGFR calculation to be adopted ↑
The equation used by the UVA Medical Laboratories to calculate estimated glomerular filtration rate (eGFR) will be updated in May. A working group from the National Kidney Foundation and American Society of Nephrology has published a new equation for calculating eGFR that is based on population data across a range of renal function but without race correction. The new equation is simpler to use (one result irrespective of race), has a low and equivalent population error for all races, and yields a more equitable distribution of resources for chronic renal disease and renal transplant across racial groups. There is a general consensus nationally that the new equation be adopted. The Clinical Laboratory Stewardship Subcommittee has reviewed the literature and recommended the new equation for routine eGFR calculation in the UVA Health System and the recommendation was approved by the Patient Care Committee. Note that the new equation estimates GFR using serum creatinine, age, and sex. Caution should be used when interpreting eGFR for transgender patients, patients with rapidly changing serum creatinine, or extremes of body composition or diet. When more accurate assessments of GFR are needed for clinical care consider measured GFR or consultation with a nephrologist.
The use of the new equation will be indicated in a comment appended to the result. The new equation supports calculation of eGFR values greater than 60 mL/min, so those results will no longer be suppressed. Providers who are trending patient results should be alert to a possible small shift in values associated with the transition to the new equation.
More detail is available from the working group report:
Delgado C, Baweja M, Crews DC, et al. A unifying approach for GFR estimation: Recommendations of the NKF-ASN Task Force on reassessing the inclusion of race in diagnosing kidney disease. American Journal of Kidney Diseases. Published online September 2021. doi:10.1053/j.ajkd.2021.08.003
Kidney Profile (LAB6302) added to orderable menu ↑
In April the UVA Clinical Laboratory added a new Kidney Profile panel (LAB6302) to the orderable test menu. The Kidney Profile combines a serum creatinine with eGFR calculation and a urine albumin/creatinine ratio into a single orderable. It was developed by the National Kidney Foundation to aid in the diagnosis, staging, and monitoring of chronic kidney disease. Its implementation at UVA was supported by InnoVAte, a project funded and overseen by the Virginia Department of Health and the CDC to prevent and control hypertension/heart disease and diabetes in high-burden populations and led at UVA by Dr. Karen Rheuban. The proposal for the new profile was reviewed and recommended by the Clinical Laboratory Stewardship Subcommittee.
- Vassalotti JA, Thavarajah S. Combined albuminuria and estimated GFR laboratory reporting affects primary care management of CKD. Kidney Med. 2020;2(3):235-238.
- National Kidney Foundation. National Kidney Foundation, American Society for Clinical Pathology, leading laboratories and clinical laboratory societies unite to diagnose chronic kidney disease.
GENOMICS PGDx Solid Tumor Gene Panel soon available ↑
Effective May 9, 2022, the Genomics Lab will begin offering the PGDx Solid Tumor Gene Panel for the detection of somatic DNA variants in common solid tumors including lung, colon, gastric and ovarian tumors, and melanoma. The test detects somatic variants in 505 genes, including single nucleotide variants, short insertions/deletions, 4 translocations and one amplification, as well as determining microsatellite instability and tumor mutational burden scores. The complete gene list can be provided by the lab upon request. The PGDx assay has been cleared by the FDA as an in vitro diagnostic device, providing more consistent reimbursement and more rigorous quality standards than our previous laboratory-developed panel. The 170-gene Solid Tumor Expanded Panel will no longer be offered.
The test name in EPIC is “Genomics PGDx Solid Tumor Gene Panel” (LAB6472)
Required Specimen: The approved specimen type is FFPE tissue with matched H&E slide, which is submitted to pathology for review and marked to indicate the area containing tumor tissue. Tumor percentage must be 20% or greater of the submitted tissue.
Schedule: The PGDx Solid Tumor Gene Panel will be performed once a week, consistent with the current Solid Tumor Expanded Panel schedule. Specimens must be received in the Clinical Genomics Laboratory by noon on Monday to be included in the batch for the week. Specimens received after this deadline will be held for analysis the following week. The transition to PGDx Solid Tumor Gene Panel will not result in a change in turnaround time for solid tumor NGS testing. Reports will continue to be available approximately 8 days after specimen batching.
Arixtra (Fondaparinux) testing converted to send-out ↑
Because of low test volume, Arixtra (Fondaparinux, formerly LAB2966), is no longer performed in the Core Lab. The test is being sent to Versiti Diagnostic Labs in Milwaukee, WI. The sendout test should be ordered as LAB3927 Miscellaneous sendout (Non-Genetic Non-Mayo). In the comment section please specify "Arixtra Level to Versiti Diagnostic Labs, order code 1009". The expected turn-around time is 2-3 days depending on time of receipt in the UVA Clinical Laboratory. The test is performed M, W, and F at Versiti.
The specimen requirement is 1 light blue tube (citrated plasma) with a minimum plasma volume of 0.3 mL. Plasma is shipped frozen.
BAL fluid cell count reporting change ↑
In May the clinical laboratory will change from reporting total cells in broncho-alveolar lavage (BAL) fluid to reporting cells per volume. This change is being made because the volume of fluid received by the laboratory may not be an accurate indication of the BAL volume and in many cases specimens must be split for culture in microbiology, which introduces additional variability. If a total cell count is needed, the total BAL volume is in the BAL procedure note in Epic and may be multiplied by the cells per volume result.
Clinical Laboratory Stewardship Subcommittee seeks clinical staff members ↑
The Clinical Laboratory Stewardship Subcommittee (CLSS) reports to the Patient Care Committee and advises the UVA Medical Laboratory. The Subcommittee seeks to maximize the value of the Medical Laboratory through review and optimization of laboratory policy, the test menu, test naming, order sets and protocols, and laboratory decision support. The CLSS welcomes participation by clinical staff from all departments who share an interest in optimizing the clinical use of laboratory testing.
Contact information:
Jim Harrison, MD PhD, jhh5y@virginia.edu
George Hoke, MD, gmh4s@hscmail.mcc.virginia.edu
Co-chairs, Clinical Laboratory Stewardship Subcommittee