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Quantitative detection of specific DNA sequences in plasma (e.g., viral or bacterial probes)

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

This test measures certain DNA fragments in your blood, often used to detect infections, genetic markers, or other genetic material.

Quick summary

["Helps identify specific genetic or infectious agents in your bloodstream."]

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

Key facts at a glance

LOINC
85785-4
Short code
C tropicls DNA Bld Pos Ql NAA+n-prb
Synonyms
C tropicls DNA Bld Pos Ql NAA+n-prb
Category
chemistry
Sample
whole-blood
Container
Lavender-top (EDTA)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
non-probe-amp-tar
Specimen volume
3 mL
Stability
Room temperature: 4h, Refrigerated: 24h
Hemolysis max
0
Lipemia max
0
Icterus max
0
TAT
4–24 hours
Order
routine

What This Test Measures

The test uses a specialized probe to detect and quantify specific DNA sequences present in your plasma. These sequences may come from viruses, bacteria, or other genetic material. The method involves a highly sensitive detection process to ensure accuracy.

Why It Might Be Ordered

Your healthcare provider may recommend this test if you have symptoms of infection, are at risk for certain diseases, or if genetic testing is needed to confirm a diagnosis. It can also be used in research or monitoring certain conditions.

Common Uses in Healthcare

Common applications include diagnosing viral infections (e.g., hepatitis, HIV), detecting bacterial DNA in bloodstream infections, or screening for genetic conditions. It may also be used in oncology to monitor tumor DNA in the bloodstream.

Sample Collection and Preparation

A blood sample is drawn from a vein, typically in your arm. The blood is then processed to separate plasma, which contains the DNA fragments being tested. This sample is sent to a lab for specialized analysis.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Frequently asked questions

How long does it take to get results from this test?
Results can vary depending on the lab and complexity of the test. Typically, results may be available within a few days to a couple of weeks, but this can differ. Your healthcare provider will discuss timelines with you during your appointment.
What does a positive result mean?
A positive result indicates the presence of the specific DNA sequences being tested for, which may suggest an infection, genetic condition, or other underlying issue. Your doctor will discuss the implications based on your clinical picture and test findings.
Can I eat or drink before this test?
For this test, you may need to follow specific instructions regarding fasting or avoiding certain foods/drinks, depending on the clinical context. Always follow your healthcare provider’s instructions for preparation.
  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