Effective June 1, 2026, Corewell Health Microbiology Laboratory in Southeast Michigan is updating specimen collection criteria for body fluid specimens. Microbiology will no longer accept red top vacutainer tubes as a collection device for body fluids (i.e. synovial fluid, pleural fluid, peritoneal fluid, etc). Collection criteria information has been updated in Corewell’s Lab Test Directory to reflect this change. Test order for body fluid cultures is LAB2111016 (aerobic culture) and commonly accompanied by LAB233 (anaerobic culture).
Orthopaedic Surgery
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:
- Ordering will be restricted to one test every 7 days.
- An indication for ordering must be provided for each order. Acceptable indications are:
- Pneumonia
- Skin and soft tissue (use for non-purulent infections)
- Surgical prophylaxis
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.
Test Information
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 |
Cell Count w/ Differential if indicated, Cerebrospinal Fluid [LAB2111025] and Cell Count with Differential, Cerebrospinal Fluid (Pediatric Oncology) [LAB212] currently result nucleated cell counts as a White Blood Cell (WBC) count.
Effective Tuesday, August 16, 2022, the WBC component will be removed and instead reported as a Total Nucleated Cell (TNC) Count for CSF.
