Carbapenem Resistant Organisms, Isolate Testing

Laboratory Fee Schedule
Procedure Number: N/A 

  • Carbapenem Resistant Enterobacterales, Carbapenem Resistant Pseudomonas aeruginosa, Carbapenem Resistant Acinetobacter baumanii, CRE, CRPA, CRAB, CRO, ARLN, Carbapenem, Antibiotic resistance, Antibiotic Susceptibility Test, PCR, Antimicrobial, MALDI-TOF, mCIM, Broth Micro Dilution
Requisition Form G-2E
Test Description
  • Definitive identification of CRO isolates by MALDI-TOF, antimicrobial susceptibility determined by broth micro dilution, and carbapenemase production determination by real-time PCR.
Pre-Approval Needed
  • N/A 
Supplemental Information Required
  • Antibiotic susceptibility report from submitter
  • Copies of any previous Lab tests (carbapenemase production or PCR), if available. 
Supplemental Form(s)
  • N/A
Performed on Specimens from (sources)
  • Human
Sample/Specimen Type for Testing
  • Pure cultured CRO isolate from any type of clinical specimen
  • Isolates should be submitted on a non-inhibitory, non-selective agar plate or/slant or broth
  • CRE isolates resistant to any imipenem, meropenem, doripenem or ertapenem
  • CRPA isolates resistant to at least one imipenem, meropenem, or doripenem AND non-susceptible (intermediate or resistant) to cefepime or ceftazidime
  • Acinetobater baumanii isolates resistant to imipenem, meropenem, or doripenem.
Minimum Volume/Size Required
  • At least one viable pure isolate per plate/slant; tube of pure culture isolate
Storage/Preservation Prior to Shipping
  • Isolates may be shipped to Laboratory at ambient temperatures
  • Ensure that growth media used does not expire before specimen collection date  
Transport Medium
  • N/A
Specimen Labeling
  • At least two patient identifiers required on specimen (e.g., patient full name, date of birth, medical record number).
  • Three patient identifiers are preferred. 
  • Identifiers on specimen must exactly match identifiers in submission form.
  • Additional DSHS Laboratory specimen labeling guidelines available online here.
Shipping and Specimen Handling Requirements
  • Ship according to Dangerous Goods Regulations, IATA, and/or CFR 49
  • Category B Biological Substance, UN3373 shipping requirements apply
  • Submitters are responsible for packaging and shipping specimens according to regulatory requirements.
  • Additional DSHS Laboratory submission guidelines available online here.
  • Identification of CRE/CRPA/CRAB by MALDI TOF.
  • Antibiotic susceptibility testing by broth micro dilution.
  • Carbapenemase production in CRE and CRPA determined by modified Carbapenem Inactivation Method (mCIM). Carbapenemase producing CRE/CRPA and CRAB identified by real-time PCR.
Turn-around Time
  • 10 working days
  • These results should be used only for epidemiological purposes and not for patient treatment.
Common Causes for Rejection
  • Mixed culture submitted 
  • Antibiotic susceptibility result from submitter not provided
  • Missing identifiers on specimen and/or submission form
  • Isolate sent not a target organism
  • Media expired at time of isolate culture
  • Mismatch between specimen and form identifiers
Additional Information
  • N/A