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Acanthamoebaabmsmtcsf

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

This test detects antibodies against Acanthamoeba in cerebrospinal fluid to diagnose rare brain infections caused by this amoeba.

Quick summary

{"This test looks for antibodies against Acanthamoeba, a microscopic organism that can infect the brain","It requires a lumbar puncture (spinal tap) to collect the cerebrospinal fluid sample","A positive result suggests an infection called Granulomatous Amoebic Encephalitis (GAE)","This is a rare but serious infection, most common in people with weakened immune systems","Results are reported as positive or negative; your doctor will interpret what this means for you"}

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

Key facts at a glance

LOINC
109427-5
Short code
ACANCSF
Synonyms
Acanthamoeba Ab Msmt CSF
Category
chemistry
Sample
csf
Container
Sterile polypropylene tube for CSF collection
Units
N/A
Ref low
0
Ref high
1
Fasting
false
Population
adult
Sex
all
Age range
≥ 0 years
Method
Immunofluorescence Assay (IFA) or Enzyme-Linked Immunosorbent Assay (ELISA)
CPT
86658 (Antibody to protozoa, not elsewhere specified)
SNOMED
124598008
Specimen volume
1-2 mL CSF minimum; 2-3 mL preferred for adequate testing
Stability
Store at 2-8°C if testing within 24 hours. For longer delays, freeze at -70°C or below. Avoid repeated freeze-thaw cycles. Transport to laboratory immediately after collection.
Hemolysis max
200
TAT
48–96 hours
Order
routine

What is this test?

The Acanthamoeba antibody test detects whether your immune system has produced specific antibodies against Acanthamoeba, a type of free-living amoeba (microscopic organism) found in soil, water, and air. When performed on cerebrospinal fluid (CSF), this test helps doctors determine if you have a brain or central nervous system infection caused by this organism.

How is the sample collected?

This test requires a sample of cerebrospinal fluid, which is the clear liquid that surrounds your brain and spinal cord. The fluid is collected through a procedure called a lumbar puncture or spinal tap. During this procedure, a healthcare provider inserts a thin needle between the bones in your lower spine to draw out the fluid. The area will be numbed with local anesthetic to reduce discomfort.

What do the results mean?

Results are typically reported as either positive (antibodies detected) or negative (no antibodies detected). A positive result suggests that you may have an infection called Granulomatous Amoebic Encephalitis (GAE), a rare but serious condition where the amoeba infects the brain. A negative result means no antibodies were found, but this does not completely rule out infection, especially in early stages. Your doctor will interpret your results along with your symptoms and other test findings.

Reference range

Negative or <1:16 titer (depending on laboratory method). Reference range may vary by laboratory method and reagent used.N/A

Specimen: csf

No special preparation required. Patient should be informed about the lumbar puncture procedure and provide informed consent. Routine CSF collection precautions should be followed.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Frequently asked questions

Why do I need this test?
Your doctor may order this test if you have symptoms of a brain or central nervous system infection, especially if you have a weakened immune system. Symptoms that might prompt this test include severe headache, fever, neck stiffness, confusion, seizures, or changes in mental status that cannot be explained by other conditions.
Is the lumbar puncture procedure painful?
The procedure itself is usually not painful because the area is numbed with a local anesthetic. You may feel some pressure or mild discomfort during the needle insertion. After the procedure, you may have a mild headache or soreness at the injection site for a day or two. Drinking plenty of fluids and resting can help reduce these symptoms.
How long does it take to get results?
This is a specialized test that is not performed at all laboratories. Results may take several days to a week or more, depending on where the sample is sent for analysis. Your healthcare provider will contact you when the results are available.
What happens if my test is positive?
If your test is positive, it indicates that you likely have a Acanthamoeba infection of the brain or central nervous system. Your doctor will discuss treatment options with you, which typically involves long-term use of antifungal and antimicrobial medications. Treatment can be challenging and may require hospitalization initially. Follow-up testing may be needed to monitor your response to treatment.
  1. 1
    Centers for Disease Control and Prevention (CDC) - AcanthamoebaSource
  2. 2
    Mayo Clinic Laboratories - Acanthamoeba Antibody, IgG, CSFSource
  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