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Laboratory Blood Test: What You Need to Know

Published: August 9, 2026Updated: August 16, 2026

This test identifies anaerobic bacteria in samples collected from the upper respiratory tract (such as the throat or nose) to help diagnose infections.

Quick summary

{"The test detects anaerobic bacteria that cannot grow in the presence of oxygen","It helps doctors diagnose specific types of respiratory infections","Results guide appropriate antibiotic treatment selection","Sample is collected using a swab from the throat or nasal passage","Results are typically available within several days"}

Medically reviewed by WellAlly Editorial TeamLast reviewed August 16, 2026Editorial policy

Key facts at a glance

LOINC
91818-5
Short code
UPRESPANA
Synonyms
Bacteria Upper resp Anaerobe Cult
Category
chemistry
Sample
serum
Container
Anaerobic transport swab or sterile anaerobic transport container; gassed-out tubes preferred
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
0–120 years
Method
anaerobic-culture
CPT
87075
SNOMED
442126005
Specimen volume
Minimum 1-2 mL of aspirate or visible material on swab
Stability
Room temperature: 2 hours; refrigerated (4°C): up to 24 hours. Specimens should be processed as soon as possible for optimal anaerobic organism recovery.
Hemolysis max
500
Lipemia max
1000
Icterus max
500
TAT
48–240 hours
Order
routine

What is this test, and why might my doctor order it for me?

The Anaerobic Bacteria Culture test is a laboratory test that detects and identifies anaerobic bacteria in samples from your upper respiratory system. Anaerobic bacteria are microorganisms that can survive and grow without oxygen. This test is different from standard bacterial cultures because it creates a special oxygen-free environment to allow these unique bacteria to grow.

How is the sample collected, and what should I expect during the appointment?

A healthcare provider will collect a sample using a sterile swab from your throat (pharynx) or nasal passage. The collection is quick and may cause mild discomfort or a gagging sensation when sampling the throat. The sample must be placed in a special transport container that maintains anaerobic conditions before being sent to the laboratory.

What do the results mean, and how will my doctor explain them to me?

If anaerobic bacteria are identified, it means you have an anaerobic bacterial infection in your upper respiratory tract. Common anaerobic bacteria found in respiratory infections include Bacteroides, Fusobacterium, and Peptostreptococcus species. Your doctor will use these results to determine the most appropriate antibiotic treatment, as some antibiotics are more effective against anaerobic bacteria than others.

Reference range

No growth of pathogenic anaerobic bacteria; normal upper respiratory flora may be presentN/A

Specimen: serum

Patient should not have eaten, drunk, or used mouthwash/oral antiseptics for at least 1 hour prior to specimen collection. Avoid antibiotic therapy prior to collection when possible.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

This test is clinically significant for diagnosing chronic or recurrent respiratory infections that may not respond to standard antibiotics. Anaerobic bacteria are often involved in conditions such as tonsillitis, sinusitis, and peritonsillar abscess (quinsy). Identifying the specific bacteria helps clinicians select targeted antibiotic therapy, improving treatment outcomes and reducing the risk of complications. This test is particularly important when patients have persistent symptoms despite conventional treatment.

Frequently asked questions

Is this test painful?
The sample collection may cause brief discomfort or a choking sensation when the swab touches the back of your throat, but the procedure is generally well-tolerated and only takes a few seconds.
How long does it take to get results?
Anaerobic bacterial cultures typically take 2-5 days to complete, as these bacteria grow more slowly than aerobic bacteria. The laboratory needs adequate time to allow the bacteria to grow and be properly identified.
Do I need to prepare for this test?
No special preparation is required. However, it is helpful to avoid eating, drinking, or using mouthwash immediately before the test, as these may affect the sample quality.
What happens if no bacteria are found?
A negative result means no anaerobic bacteria were detected in your sample. This could mean your symptoms are caused by a different type of infection (viral or aerobic bacterial), or that the infection is in a different location. Your doctor will consider these results along with your symptoms and other test findings to determine next steps.
  1. 1
    Mayo Clinic Laboratories - Anaerobic CultureSource
  2. 2
    American Society for Microbiology - Clinical Microbiology ProceduresSource

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.

Medical Disclaimer

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