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16S rRNA Gene Detection in Body Fluid DNA by Probe-Based Assay

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

This test checks for the presence of bacterial DNA in your body fluids, specifically targeting the 16S ribosomal RNA gene. It helps identify potential bacterial infections by detecting genetic material from bacteria.

Quick summary

This test may help diagnose infections when other tests are unclear or when bacteria are suspected but not yet confirmed.

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

Key facts at a glance

LOINC
76603-0
Short code
BACT16S
Synonyms
Bact 16S rRNA # XXX.body fld NAA+probe
Category
chemistry
Sample
serum
Container
Sterile, DNA-free, nuclease-free collection tube (e.g., EDTA tube, sterile plasma/serum tube, or specialized molecular transport tube) specific to specimen type; for body fluids use sterile screw-cap containers
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
≥ 0 years
Method
probe-amp-tar
CPT
87801
SNOMED
441951000124106
Specimen volume
1-5 mL of body fluid depending on specimen type and assay requirements; minimum 0.5 mL for most commercial assays
Stability
Room temperature: 2-4 hours; Refrigerated (2-8°C): up to 24-48 hours; Frozen (-70°C or below): up to 1 month for delayed processing. Avoid repeated freeze-thaw cycles. EDTA whole blood should be processed within 24 hours.
Hemolysis max
500
Lipemia max
1000
Icterus max
500
TAT
4–72 hours
Order
routine

What This Test Measures

The 16S rRNA gene is a conserved region in bacterial DNA that is unique to bacteria. By detecting this gene, the test can identify a wide range of bacterial species, even if their specific identity is unknown. This is particularly useful in situations where traditional bacterial cultures take time or fail to grow detectable bacteria.

Why It Might Be Ordered

Your healthcare provider may order this test if you have symptoms suggestive of a bacterial infection, such as fever, chills, or signs of infection in a specific area (e.g., blood, urine, or other body fluids). It can also be used in cases where cultures are negative but clinical suspicion remains high, or in research or diagnostic contexts where bacterial identification is critical.

Sample Collection and Preparation

A sample of your body fluid (e.g., blood, urine, or other bodily secretions) is collected and processed to extract DNA. This DNA is then analyzed using a probe that binds specifically to the 16S rRNA gene of bacteria.

Limitations and Considerations

This test detects bacterial DNA but does not distinguish between live and dead bacteria. It may also yield false positives if non-bacterial DNA is present or if contamination occurs. Results should be interpreted by a healthcare professional in the context of clinical symptoms and other diagnostic findings.

Reference range

Not Detected (Negative). Results reported as detected/not detected or estimated bacterial load [#/volume] depending on the assay format. Quantitative results vary by specimen type and clinical context; consult laboratory-specific reference values.N/A

Specimen: serum

No special patient preparation is required. However, sample collection should occur prior to initiation of antimicrobial therapy whenever possible to maximize diagnostic yield. For blood cultures, proper skin antisepsis is essential to minimize contamination.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical Significance

Short name

Bacterial 16S rRNA Probe Test

Frequently asked questions

How long will it take to get my results?
Results from this test are typically available within a few days to a couple of weeks, depending on the laboratory’s workflow and the complexity of the analysis. Your healthcare provider will discuss the results with you and may recommend further testing or treatment based on the findings.
Can this test replace traditional bacterial cultures?
While this test provides a rapid and sensitive way to detect bacterial DNA, it is not a replacement for traditional bacterial cultures in all cases. Cultures can confirm the identity of bacteria and assess antibiotic susceptibility, which are critical for guiding appropriate treatment.
What if the test is positive for bacterial DNA?
A positive result indicates the presence of bacterial DNA, suggesting a possible bacterial infection. Your healthcare provider will evaluate the results alongside your clinical symptoms, other diagnostic tests, and patient history to determine the best course of action, which may include antibiotics or further diagnostic testing.
  1. 1
    MedlinePlus — Laboratory TestsSource
  2. 2
    Lab Tests OnlineSource
  3. 3
    Mayo Clinic — Tests & 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