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Plasma RNA Viral Load (e.g., SARS-CoV-2, Influenza, or Other Respiratory Viruses) by Probe-Based Assay

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

This test measures the amount of genetic material from certain viruses in your blood. It helps doctors track how your infection is progressing or responding to treatment.

Quick summary

["This test helps monitor viral infections in your bloodstream."]

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

Key facts at a glance

LOINC
23371-8
Short code
PRRSV RNA Smn Ql NAA+probe
Synonyms
PRRSV RNA Smn Ql NAA+probe
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
probe-amp-tar
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

Why This Test Is Done

Doctors may order this test if you have symptoms of a viral infection, such as fever, cough, or fatigue, and suspect you might be infected with a virus like COVID-19, flu, or another respiratory virus. It can also be used during treatment to check if the virus is decreasing or if your body is responding to medication.

What to Expect Before the Test

No special preparation is usually needed. You may have a small needle inserted into your arm to draw a blood sample. If you’re on blood thinners or have a history of bleeding issues, let your doctor know before the test.

What the Test Results Mean

Results show the presence and quantity of viral RNA in your blood. High levels may indicate an active infection, while very low or undetectable levels could mean the virus is under control or gone. Your doctor will interpret the results in the context of your symptoms and medical history.

Common Causes of Viral Infections Monitored by This Test

This test is often used for respiratory viruses like SARS-CoV-2 (COVID-19), influenza (flu), respiratory syncytial virus (RSV), or other viruses that can cause similar symptoms. It’s also used in research or specialized care for other viral infections.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

Viral RNA Load (Plasma)

Frequently asked questions

What does a positive result mean?
A positive result means your blood contains detectable viral genetic material, confirming an active infection with the virus being tested for. This doesn’t always mean you’re contagious right away, but it indicates the virus is present and may be spreading in your body.
Can this test detect all viruses?
This test is designed to detect specific viruses based on the probe used. It may not detect all possible viruses, so if you suspect another infection, your doctor may recommend additional tests.
How often should I get this test?
Your doctor will determine the frequency based on your symptoms, treatment plan, and the virus being monitored. It might be done weekly during acute infection or less often if you’re in recovery or stable.
  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