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Cva9abmsmtcsf

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

This test detects antibodies against Coxsackievirus A9 in the cerebrospinal fluid (CSF), helping diagnose viral infections affecting the central nervous system.

Quick summary

{"Measures antibodies to Coxsackievirus A9 in brain/spinal fluid","Helps diagnose viral meningitis, encephalitis, or CNS infections","Sample is collected via lumbar puncture (spinal tap)","Positive result indicates current or recent infection","Often ordered when patients show neurological symptoms with suspected viral cause"}

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

Key facts at a glance

LOINC
109455-6
Short code
CV-A9 CSF Ab
Synonyms
CV A9 Ab Msmt CSF
Category
cardiac
Sample
csf
Container
Sterile polypropylene CSF collection tube (preferably polypropylene or glass tube, not cotton-plugged). Two to three tubes should be collected: Tube 1 for chemistry/microbiology, Tube 2 for cell count, Tube 3 for serology/PCR. Transport tubes should be clean and dry.
Units
N/A
Ref low
1
Ref high
1.5
Fasting
false
Population
adult
Sex
all
Age range
0–120 years
Method
Enzyme-Linked Immunosorbent Assay (ELISA)
CPT
86658 (Antibody; Coxsackievirus)
SNOMED
122444000
Specimen volume
Minimum 1.0 mL CSF; preferred 2-3 mL for comprehensive analysis including multiple tests
Stability
Refrigerated (2-8°C): up to 72 hours for antibody testing; Frozen (-20°C or below): up to 2-4 weeks for long-term storage. Avoid repeated freeze-thaw cycles. Ship on dry ice if transport exceeds 72 hours.
Hemolysis max
200
TAT
48–168 hours
Order
routine

What is this test?

The Coxsackievirus A9 antibody test is a laboratory test that detects specific antibodies (IgM and IgG) against Coxsackievirus A9 in the cerebrospinal fluid (CSF). CSF is the clear fluid that surrounds the brain and spinal cord. This test helps healthcare providers determine if a viral infection is affecting the central nervous system.

How is the sample collected?

The CSF sample is collected through a procedure called a lumbar puncture, also known as a spinal tap. A healthcare provider inserts a thin needle into the lower back to withdraw a small amount of cerebrospinal fluid. This procedure is typically performed by a trained physician and takes about 15-30 minutes.

Why might I need this test?

Your doctor may order this test if you have symptoms suggesting a central nervous system infection, such as fever, headache, stiff neck, confusion, or seizures. It is particularly useful when viral meningitis or encephalitis is suspected, especially if there is a known outbreak of Coxsackievirus infections in the community.

Reference range

Negative: < 1:2 titer or < 1.0 (index value); Equivocal: 1:2 to 1:4 titer or 1.0-1.5 (index value); Positive: >= 1:4 titer or >= 1.5 (index value). Presence of CSF-specific IgM or significant rise in IgG titer between acute and convalescent samples indicates recent or active infection.N/A

Specimen: csf

No fasting required. Patient should be properly consented for lumbar puncture. Inform patient of risks including headache, bleeding, or infection at puncture site. Obtain relevant clinical history including onset of neurological symptoms, recent infections, and vaccination status.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Frequently asked questions

Does a positive result mean I definitely have a Coxsackievirus infection?
A positive result for IgM antibodies in CSF strongly suggests a current or recent Coxsackievirus A9 infection affecting the central nervous system. Your doctor will interpret the results in combination with your symptoms, physical examination, and other test results.
Is the lumbar puncture procedure painful?
You may feel some discomfort or pressure during the lumbar puncture. A local anesthetic is usually used to numb the area, which helps reduce pain. Some patients experience a mild headache afterward, which can be managed with rest and fluids.
How long does it take to get results?
Results typically take 2-5 days, depending on the laboratory. The test requires specialized testing methods to detect antibodies in the cerebrospinal fluid.
Is this test different from a blood test for Coxsackievirus?
Yes. This test specifically measures antibodies in the cerebrospinal fluid, which directly indicates whether the virus has affected the central nervous system. Blood tests detect antibodies in the bloodstream and may indicate systemic infection but cannot confirm CNS involvement.
What is the treatment if the test is positive?
Treatment is primarily supportive care, as most Coxsackievirus infections are self-limiting. This may include rest, fluids, pain relievers for fever and discomfort, and close monitoring. In severe cases, hospitalization may be required. Antiviral medications are not typically needed for uncomplicated cases.
  1. 1
    CDC - Coxsackievirus and EnterovirusSource
  2. 2
    Mayo Clinic Laboratories - Coxsackievirus A9 AntibodySource
  3. 3
    Johns Hopkins Medicine - Lumbar Puncture (Spinal Tap)Source

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