Erythromycin Resistance Screening in Slow-Growing Mycobacteria (e.g., *Mycobacterium ulcerans*)
This test checks whether certain slow-growing bacteria, like those that cause skin ulcers or lung infections, may be resistant to the antibiotic erythromycin. Resistance means the bacteria could grow even with this medication.
["Helps guide treatment choices for infections caused by slow-growing mycobacteria."]
Key facts at a glance
- LOINC
- 20380-2
- Short code
- Erythromycin Islt SlowMyco
- Synonyms
- Erythromycin Islt SlowMyco
- Category
- chemistry
- Sample
- serum
- Container
- Red-top tube (SST)
- Units
- N/A
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- Method
- method-for-slow-growing-mycobacteria
- Specimen volume
- 5 mL
- Stability
- Room temperature: 4h, Refrigerated: 24h, Frozen: 7d
- Hemolysis max
- 500
- Lipemia max
- 1000
- Icterus max
- 500
- TAT
- 4–24 hours
- Order
- routine
What This Test Measures
The test detects genetic markers that indicate whether the slow-growing mycobacteria in your sample may resist erythromycin. This is done through a specialized laboratory method that identifies changes in the bacteria’s DNA related to antibiotic resistance.
Why It’s Ordered
Your healthcare provider may order this test if you have symptoms of slow-growing mycobacterial infections (e.g., skin ulcers, persistent lung infections) and erythromycin is being considered as part of treatment. It helps ensure the right antibiotics are chosen to effectively treat the infection.
Sample Collection and Preparation
The test uses a sample of slow-growing mycobacteria cultured from a bodily fluid or tissue (e.g., skin lesion, sputum, or biopsy). The bacteria are grown in the lab, and genetic testing is performed on a small sample of these cultures.
What to Expect Before the Test
No special preparation is needed beyond following your healthcare provider’s instructions for collecting the sample (e.g., avoiding certain medications or procedures). If you’re taking antibiotics, let your lab know to avoid false results.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
Positive results suggest the bacteria may not respond to erythromycin, which could mean your treatment plan needs adjustment. Negative results indicate the bacteria are likely sensitive to erythromycin, supporting its use. This testing helps prevent unnecessary antibiotic resistance and improves infection outcomes.
Short name
Erythromycin Resistance Test (Slow-Growing Mycobacteria)
Frequently asked questions
What does a positive result mean?
What if my test is negative?
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