Effective October 3, 2023, Corewell Health Laboratories will discontinue the Influenza Rapid and Respiratory Syncytial Virus (RSV) Rapid tests. These antigen tests are less sensitive than the nucleic acid amplification tests (NAAT; such as PCR) that are now the standard of care for diagnosing these respiratory viruses. Specimen collection remains unchanged with PCR testing available for nasopharyngeal and nasal swabs collected in a universal transport media (UTM) tube.
• Influenza (Flu) A/B Rapid – Epic Code: LAB9240
• Influenza (Flu) A/B Rapid, Influenza A/B PCR if Negative – Epic Code: LAB2111530
• Respiratory Syncytial Virus (RSV) Rapid – Epic Code: LAB495
• Influenza (Flu) A/B PCR – Epic Code: LAB3255
• COVID-19, Influenza A/B, RSV PCR – Epic Code: LAB1230746
The management of sinusitis is often aided by bacterial and fungal cultures from which Streptococcus pneumoniae, Haemophilus influenzae, Moraxella catarrhalis, Staphylococcus aureus, and occasionally aerobic Gram-negative bacilli are the most commonly recovered pathogenic organisms. The Corewell Health West Microbiology Lab has several orders available for culturing sinus specimens collected as fluid aspirates, tissue, or swabs. Though more challenging to collect, aspirates are preferred over swab cultures that often grow mixed normal upper respiratory flora for which it is difficult to interpret the clinical significance.
The Enteric Pathogens PCR test performed by Spectrum Health Laboratory may be used to detect common pathogenic bacteria and viruses in stool collected from individuals with symptoms of gastrointestinal infection. Specifically, this test detects Campylobacter, Salmonella, Shigella, Vibrio, Yersinia enterocolitica, Norovirus, Rotavirus, and the Shiga toxin virulence factor. Effective August 17, 2022, Spectrum Health’s Epic EMR will contain new ask-at-order questions to help improve the clinical decision support and appropriate utilization of this testing.
Effective May 9th, 2022, Spectrum Health Laboratory’s Microbiology Department will no longer be preemptively setting up cultures on swabs without a source and order, when received on Thursdays through Sundays and Holidays. Note: The specimen will still be held, but cultures will not be set up in anticipation of the order.
As of April 12, 2022, Spectrum Health Laboratory will no longer add microbiology cultures to placental tissues received based on paper requisition forms.
Viral and bacterial cultures from placental tissue are rarely clinically beneficial and are no longer the gold standard diagnostic approach due to the relative insensitivity of culture methods.
If viral studies are desired (possible indications could include known CMV exposure with positive IgM or intrauterine fetal demise at < 28 weeks), then molecular testing is the recommended diagnostic approach. HSV and CMV PCR tests may be ordered in Epic.
• Herpes Simplex 1/2 Qualitative PCR, Tissue (LAB1230413)
• Cytomegalovirus (CMV) Qualitative PCR, Tissue (LAB1230291)
Bacterial cultures are challenging to interpret since they typically grow normal genital flora and histopathological analysis used to diagnose acute chorioamnionitis correlates poorly with growth from bacterial placenta cultures. If indicated, culture and PCR tests may be ordered in Epic.
• Tissue Culture (LAB2111173)
• Metamycoplasma hominis, Molecular Detection, PCR, Varies (LAB848)
• Ureaplasma species, Molecular Detection, PCR, Varies (LAB848)
Placenta tissues sent to the lab in formalin are not acceptable for PCR or culture orders.
As of April 5th, 2022, Herpes Simplex viral PCR testing will transition from being performed in the Spectrum Health Molecular department to the Microbiology department. There are no changes to the acceptable specimen sources for this test (cerebrospinal fluid and blood plasma specimens). Benefits of the new Microbiology testing method include:
• The new test method (DiaSorin Simplexa® HSV PCR) is FDA-cleared for testing spinal fluid specimens with a validated modification for testing plasma specimens. The prior method was a lab-developed test for both specimen types.
• Especially for pediatric patients, collecting sufficient specimen volumes can sometimes be challenging. The new method requires a minimum of 0.05 mL specimen per run whereas the prior method required 0.2 mL specimen.
• The frequency of testing will increase from typically one run per day to testing being performed at several times each day.
As of March 21, 2022, Spectrum Health Laboratories will adopt a new C. difficile testing approach that no longer reflexes to PCR testing for indeterminate toxin enzyme immunoassay (EIA) results. Rather, PCR testing will only be available upon consultation with Infectious Disease.
Effective February 10, 2022, Spectrum Health Regional Laboratory will offer Varicella Zoster Virus (VZV) PCR testing on swab specimens collected from cutaneous and mucocutaneous lesions (e.g. anorectal, genital, nasal, ocular, oral, skin, urethral).
PCR is the test method of choice for the diagnosis of VZV infection due to its enhanced sensitivity and speed as compared to traditional viral cultures, which should no longer be used for VZV detection.
The mitigation strategies enacted during the COVID-19 pandemic to reduce the spread of this virus led to essentially non-existent influenza prevalence during the 2020-2021 winter season. However, influenza has now returned and case numbers are increasing throughout West Michigan.
Influenza prevalence guides the most appropriate testing approach and sufficient prevalence has now been reached for influenza rapid antigen testing (e.g. Sofia instrument) to have improved performance. The use of rapid antigen testing as a screening method during high prevalence reduces both the cost to the patient and turn-around-time as compared to lab-based molecular methods. Rapid antigen tests generally have high analytical specificity, but lack the sensitivity of nucleic acid amplification methods (e.g. PCR). For this reason, PCR testing is still recommended for hospitalized patients and for outpatients with a negative antigen result if influenza is still suspected and if the result will impact clinical decision making.
The mitigation strategies enacted during the COVID-19 pandemic to reduce the spread of this virus have also impacted the transmission of other respiratory viruses. Influenza is typically prevalent during the winter months (December through March), however, influenza cases were essentially non-existent during the 2020-2021 season and influenza is not currently circulating in our community.
In the absence of circulating influenza activity, it is recommended to use the most sensitive diagnostic test in order to obtain accurate and actionable results. Influenza antigen testing (e.g. Sofia instrument) is not appropriate at this time. More detailed information can be found as published by the CDC: Algorithm to assist in the interpretation of influenza testing results and clinical decision-making during periods when influenza viruses are NOT circulating in the community