On March 21, 2017, Spectrum Health Regional Laboratory (SHRL) will be switching instrument/vendors that perform the Beta CTX (BCTX assay); we will be switching from the ROCHE COBAS® platform to the ISYS-IDS platform. Both methods compare very well, however reference ranges will change due to the different methods.
Spectrum Health Regional Laboratory is preparing to switch Clostridium difficile testing methods from solely using a molecular approach to a 2-step algorithm utilizing an Enzyme Immunoassay (EIA) that detects two C. difficile-specific proteins (glutamate dehydrogenase or GDH, and A/B toxin) with indeterminant EIA specimens reflexed to PCR (see flowchart below). It is estimated that approximately 90% of patients tested will be resolved by EIA and not require reflexive PCR testing. This algorithm decreases expenses to the patient by an average of 65% as compared to current testing without sacrificing result quality. Specimens will be batched for EIA testing at a frequency to ensure that results are available within 6 hours of receipt by the laboratory so that proper contact isolation precautions may be initiated when indicated.
In anticipation of “Flu season”, it is valuable to revisit available testing methods for influenza and discuss when each test should be ordered. Though generally a self-limited infection for otherwise healthy individuals, influenza can be particularly severe for high-risk populations including infants, elderly, pregnant women, and immunocompromised hosts. Influenza incidence is largely seasonal with the majority of cases occurring between December and April of each year.
Effective August 18, 2016, the Spectrum Health Regional Laboratory Microbiology Department will begin offering the Verigene® Enteric Pathogens Test, a new rapid molecular test that simultaneously detects and identifies the following pathogenic enteric bacteria, viruses, and toxins that commonly cause acute community-acquired diarrhea. Testing occurs directly from stool in Cary-Blair preservative with a 1 day turnaround time (2-3 days faster than current methods).
Tests not performed by Spectrum Health Regional Laboratories (SHRL) will be sent to an appropriate reference laboratory. Mayo Medical Laboratories is our major reference lab; however, not all tests are performed at that location. Please refer to the laboratory test catalog for specific testing locations. (http://spectrumhealth.testcatalog.org/)
On September 1, 2015, Spectrum Health Regional Laboratory, in conjunction with Infectious Disease, Infection Prevention and Pharmacy, adjusted reflex criteria for urine culture based on urinalysis finding (Urinalysis, Do Culture if Indicated – Test #115, Epic #LAB348, UA CX DO IF). The adjustment involved an increase in the number of WBCs per HPF considered positive (from ≥3 to ≥10).
Cardiac marker (Troponin) testing should only be ordered for Inpatient or Emergency Department patients. This test is not clinically appropriate for outpatient testing due to long outpatient test turnaround time (specimen collection to result). In cases of acute/urgent medical conditions, please have the patients evaluated at an Urgent Care center or the Emergency Department.
Thyroid Peroxidase Antibody (anti-TPO), Blood Level (Test #8524 )
This is the recommended test for the evaluation of Autoimmune Thyroiditis
Thyroglobulin, Tumor Marker, Serum (Test #3069)
It is only indicated for monitoring of thyroid cancer treatment.
This result is reported with an Anti-Tg result to assess for possible interference.
This test should NOT be ordered for associated anti-Tg result provided by reference laboratory.
Thyroglobulin Antibody (anti-Tg) Test
Historically ordered with anti-TPO for evaluation of possible autoimmune thyroiditis.
The literature shows that anti-TPO, alone, has better sensitivity and specificity with only 5% of cases of Autoimmune thyroiditis with anti-TPO negative, anti-Tg positive.
Since 2/2011, requests for anti-Tg have been cancelled per Laboratory Communication: Memo Thyroglobulin Antibody 2/2011
Spectrum Health Regional Laboratory Experience February 2015 – March 2016 (13 months):
357 patients with both Anti-TPO and Anti-Tg results.
*Anti-Tg results were due to concomitantly ordered Thyroglobulin TM requests.
250 patients had positive Anti-TPO and/or Anti-Tg level
193 patients had both positive Anti-TPO and Anti-Tg level
56 patients had positive Anti-TPO and negative Anti-Tg level
1 patient had a negative Anti-TPO and positive Anti-Tg levels
Based on these results, and what is reported in the literature, we are confident of our current practices and strongly request discontinuation of Thyroglobulin TM requests for the associated Anti-Tg result
Caturegli P, De Remigis A, Rose NR. Hashimoto thyroiditis: clinical and diagnostic criteria. Autoimmun Rev. 2014 Apr-May;13(4-5):391-7