Key Update
Effective July 29, 2026, inpatient Enteric Pathogens PCR Panel (LAB3618) orders will be restricted when screening criteria are not met.
Effective Date: September 3, 2025
The MRSA Screen PCR [LAB1231076] detects the presence or absence of colonization with methicillin-resistant Staphylococcus aureus (MRSA) and may be used to guide antimicrobial prophylaxis decisions. To improve and standardize test utilization across all Corewell Health regions, the following restrictions will be added to this test order:
Studies have shown that there is minimal utility in re-testing within 2 weeks as MRSA conversion rates are low and the PCR negative predictive values remain high for at least 14 days after initial testing.
Absence of nasal colonization with MRSA cannot be used to reliably rule out MRSA infection in scenarios other than those listed above.
Influenza prevalence fluctuates seasonally, and case numbers are currently increasing throughout West Michigan. The onset of “flu season” varies year-to-year though typically begins its upswing in the month of December. It is important for providers to have an awareness of influenza prevalence (in addition to other respiratory viruses) to help guide when influenza testing should be pursued.
The use of point of care (POC) antigen testing reduces both the cost to the patient and turn-around-time as compared to lab-based molecular methods. POC antigen tests are typically available for COVID-19, influenza A/B, and as a COVID-19/influenza A/B combination test. During warmer months when influenza prevalence is negligible yet COVID-19 may be circulating, a COVID-only antigen test may be helpful for diagnosis. As influenza increases into colder months, a COVID-19/Influenza A/B combo test would act as a screen for both viruses.
POC 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 POC result if influenza is still suspected and if the result will impact clinical decision making. Influenza PCR may be ordered as a standalone test (LAB3255) or as a part of a panel alongside COVID-19 and RSV (LAB1230746).
Local Infection Prevention Team
Michigan Department of Health and Human Services
This winter, West Michigan influenza infections peaked in February 2024 and significantly declined throughout March and April 2024. Now with a low prevalence of circulating influenza, using the most sensitive diagnostic test is recommended in order to obtain accurate and actionable results. Influenza antigen testing (e.g. Sofia instrument) is no longer appropriate at this time and Influenza PCR testing should be ordered when clinically indicated.
| Low Influenza Prevalence |
High Influenza Prevalence |
|
| Recommended Order | Influenza PCR (LAB3255) | Influenza antigen testing (e.g. Sofia instrument) or Influenza PCR (LAB3255) |
More detailed information can be found as published by the CDC:
Influenza cases numbers are currently increasing throughout West Michigan. Influenza prevalence guides the most appropriate testing approach and sufficient prevalence has now been reached for influenza rapid antigen or point of care testing (e.g. Sofia instrument) to have improved performance. The use of point of care 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. Point of care 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 result if influenza is still suspected and if the result will impact clinical decision making.
| Low influenza prevalence | High influenza prevalence | |
| Recommended order | Influenza PCR | Influenza Point of Care Testing or Influenza PCR |
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.
Discontinued:
• 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
Replace with:
• Influenza (Flu) A/B PCR – Epic Code: LAB3255
• COVID-19, Influenza A/B, RSV PCR – Epic Code: LAB1230746
Effective September 13, 2023, Corewell Health Laboratory will discontinue the Chlamydia Culture orderable. For patients 14 years of age and older, please order Chlamydia PCR.
• This specimen can be either a swab (genital, rectal, or throat) or a urine sample.
• The collection container is the STD-Multi-Collection Kit.
• For more information please visit: Chlamydia PCR
For patients that are under 14 years of age, a “Reference Miscellaneous Test” [LAB 848], must be ordered.
• This specimen can be either a swab (genital, rectal, or throat) or a urine sample.
• The collection container is the Aptima
• For more information please visit: APTIMA Chlamydia, NAAT, ThinPrep, Swab, Urine
As a reminder, PCR testing is also preferred for gonorrhea, when the specimen types are compatible.
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.
| Available Sinus Culture Orders | Default Specimen Type | Comments |
| Body Fluid Culture [LAB2111016]
Respiratory Culture [LAB3095] Tissue Culture [LAB2111173] |
Aspirated fluid
Swabbed collection Tissue |
For aerobic bacteria |
| Fungal Culture [LAB240] | Aspirated fluid or tissue, preferred
Swabbed collection |
For fungal organisms |
| Anaerobic Culture [LAB233] | Aspirated fluid or tissue* | For anaerobic bacteria |
This winter, West Michigan influenza infections peaked in December 2022 and significantly declined throughout February and March 2023. Now with a low prevalence of circulating influenza, using the most sensitive diagnostic test is recommended in order to obtain accurate and actionable results. Influenza antigen testing (e.g. Sofia instrument) is no longer appropriate at this time and Influenza PCR testing should be ordered when clinically indicated.