Carbapenemase Detection (Qualitative, by Specimen Probe)
This test checks for the presence of carbapenemase enzymes in a sample, which are bacteria-produced proteins that can break down carbapenem antibiotics—a key class of drugs used to treat serious infections.
["Helps identify bacteria resistant to powerful antibiotics, guiding treatment choices."]
Key facts at a glance
- LOINC
- 74676-8
- Short code
- CARBNP
- Synonyms
- Carbapenemase Islt
- Category
- chemistry
- Sample
- serum
- Container
- Pure bacterial isolate on appropriate solid media (e.g., Mueller-Hinton agar, blood agar, or MacConkey agar) in sealed petri dish or screw-cap tube. Alternatively, isolate in nutrient broth or transport medium. Ensure container is leak-proof and labeled with patient and isolate identification.
- Units
- N/A
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- Method
- carbapenemase-nordmann-poirel
- CPT
- 87185
- SNOMED
- 417980004
- Specimen volume
- Sufficient pure bacterial growth to prepare a heavy inoculum suspension equivalent to at least one full 10 µL loop of bacterial culture, typically from a single isolated colony.
- Stability
- Bacterial isolates should be tested within 18-24 hours of growth for optimal results. Isolates on agar plates can be stored at 2-8°C for up to 7 days. Long-term storage requires freezing at -80°C in appropriate cryopreservation medium (e.g., skim milk or glycerol stocks). Repeated subculturing should be avoided as it may affect carbapenemase expression.
- Hemolysis max
- 500
- Lipemia max
- 1000
- Icterus max
- 500
- TAT
- 2–24 hours
- Order
- routine
What This Test Measures
Carbapenemase enzymes are produced by certain bacteria, such as *Klebsiella*, *Escherichia coli*, or *Pseudomonas*, that can cause infections resistant to carbapenems. This test detects their activity in a sample, often from urine, blood, or other clinical specimens, to confirm resistance.
Why It’s Done
Doctors may order this test if you have a suspected infection caused by bacteria that may produce carbapenemases, particularly in settings like hospitals or long-term care facilities where such resistance is more common.
Sample Collection and Processing
The test uses a probe-based method to detect carbapenemase activity directly from a clinical specimen (e.g., urine, blood, or wound swab). No fasting or special preparation is needed, but the sample must be collected and processed according to lab protocols.
What It Means for Your Health
A positive result indicates the presence of carbapenemase-producing bacteria, which may require alternative antibiotics or additional monitoring. A negative result suggests the bacteria are likely sensitive to carbapenems, but further testing may still be needed.
Reference range
Negative: No carbapenemase activity detected (phenol red remains red/orange). Positive: Carbapenemase activity detected (phenol red turns yellow within 2 hours, indicating imipenem hydrolysis and decrease in pH). The Carba NP test detects carbapenemase production in Enterobacteriaceae, Pseudomonas aeruginosa, and Acinetobacter spp.N/A
This test is performed on bacterial isolates cultured from clinical specimens, not directly on patient samples. No patient preparation is required. The isolate should be a fresh, pure culture (18-24 hours old) from a primary isolation plate. Submit pure bacterial colony on agar plate or in appropriate transport medium.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
Carbapenemase-producing bacteria are a growing public health concern as they can cause severe infections that are difficult to treat. Early detection helps healthcare providers choose the most effective antibiotics and prevent spread of resistant bacteria in healthcare settings.
Short name
Carbapenemase Screen
Frequently asked questions
What does a positive result mean?
How long does it take to get results?
Can I take antibiotics before this test?
Sources
- 1
- 2Lab Tests OnlineSource
- 3
Click any link to access the full source. PubMed Central (PMC) links provide free full-text access.
This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.
This content is for general informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified healthcare provider with any questions you have about a medical condition, and never disregard professional medical advice or delay seeking it because of something you read here.
If you think you may have a medical emergency, call your local emergency number or go to the nearest emergency department immediately.
Medically reviewed by WellAlly Editorial Team Last reviewed August 16, 2026. · Read our editorial policy