CPT® Code 86789

Official Description

Antibody; West Nile virus

Common Language Description

The CPT® Code 86789 refers to the laboratory test for detecting antibodies specific to the West Nile virus. This test is crucial for diagnosing infections caused by the West Nile virus, which can lead to serious neurological diseases. The antibody test specifically measures the presence of immunoglobulin M (IgM) antibodies, which are produced by the immune system in response to the virus. The testing process typically involves collecting blood serum or cerebrospinal fluid (CSF) samples from patients who exhibit symptoms of West Nile virus infection. It is important that these samples are collected within a specific timeframe, ideally between 8 to 21 days after the onset of symptoms, to ensure accurate results. The testing protocol often includes an initial serum sample followed by a second sample taken at least two weeks later, allowing for the assessment of changes in antibody levels during the acute and convalescent phases of the infection. The most reliable method for confirming the presence of IgM antibodies is through the IgM antibody capture enzyme-linked immunosorbent assay (MAC-ELISA), particularly when analyzing CSF samples. This is because IgM antibodies do not cross the intact blood-brain barrier; thus, their detection in CSF is a strong indicator of a central nervous system infection. Additionally, plaque-reduction neutralizing tests can be performed on paired serum or CSF samples collected at least two weeks apart, with a four-fold increase in antibody titer serving as confirmation of West Nile virus infection.

1. Indications

The antibody test for West Nile virus (CPT® Code 86789) is indicated for the following conditions:

Suspected West Nile Virus Infection Patients presenting with symptoms consistent with West Nile virus infection, such as fever, headache, body aches, and neurological symptoms, may require testing to confirm the presence of the virus.
Monitoring of Antibody Response The test is also used to monitor the immune response in patients who have been previously diagnosed with West Nile virus, particularly during the acute and convalescent phases of the illness.

2. Procedure

The procedure for testing antibodies to the West Nile virus involves several key steps:

Sample Collection Blood serum or cerebrospinal fluid (CSF) samples are collected from the patient. It is essential that these samples are obtained within 8 to 21 days following the onset of symptoms to ensure the accuracy of the test results.
Initial Testing The first serum sample is analyzed for the presence of West Nile virus-specific IgM antibodies. This initial test is crucial for determining whether the patient has been exposed to the virus.
Follow-Up Sample Collection A second serum sample is collected at least two weeks after the initial sample. This follow-up is necessary to assess the change in antibody levels, which can indicate the progression of the infection.
Testing Methodology The most specific test for confirming the presence of IgM antibodies is the IgM antibody capture enzyme-linked immunosorbent assay (MAC-ELISA), particularly when analyzing CSF samples. This method is preferred due to its high specificity for detecting IgM antibodies in the central nervous system.
Neutralization Testing In addition to the IgM testing, plaque-reduction neutralizing tests may be performed on paired serum or CSF samples. This involves comparing the antibody titers from the initial and follow-up samples, with a four-fold increase in titer confirming the presence of West Nile virus infection.

3. Post-Procedure

After the antibody testing for West Nile virus is completed, the results are analyzed and interpreted by healthcare professionals. Patients may be monitored for any symptoms or complications arising from the infection. If the test results indicate a confirmed infection, appropriate clinical management and follow-up care will be initiated based on the severity of the symptoms and the patient's overall health status. It is important for healthcare providers to communicate the results to the patient and discuss any necessary next steps in their care plan.

Short Descr	WEST NILE VIRUS ANTIBODY
Medium Descr	ANTIBODY WEST NILE VIRUS
Long Descr	Antibody; West Nile virus
Status Code	Statutory Exclusion (from MPFS, may be paid under other methodologies)
Global Days	XXX - Global Concept Does Not Apply
PC/TC Indicator (26, TC)	9 - Not Applicable
Multiple Procedures (51)	9 - Concept does not apply.
Bilateral Surgery (50)	9 - Concept does not apply.
Physician Supervisions	09 - Concept does not apply.
Assistant Surgeon (80, 82)	9 - Concept does not apply.
Co-Surgeons (62)	9 - Concept does not apply.
Team Surgery (66)	9 - Concept does not apply.
Diagnostic Imaging Family	99 - Concept Does Not Apply
CLIA Waived (QW)	No
APC Status Indicator	Conditionally packaged laboratory tests
Type of Service (TOS)	5 - Diagnostic Laboratory
Berenson-Eggers TOS (BETOS)	T1H - Lab tests - other (non-Medicare fee schedule)
MUE	2
CCS Clinical Classification	235 - Other Laboratory

90	Reference (outside) laboratory: when laboratory procedures are performed by a party other than the treating or reporting physician or other qualified health care professional, the procedure may be identified by adding modifier 90 to the usual procedure number.
26	Professional component: certain procedures are a combination of a physician or other qualified health care professional component and a technical component. when the physician or other qualified health care professional component is reported separately, the service may be identified by adding modifier 26 to the usual procedure number.
91	Repeat clinical diagnostic laboratory test: in the course of treatment of the patient, it may be necessary to repeat the same laboratory test on the same day to obtain subsequent (multiple) test results. under these circumstances, the laboratory test performed can be identified by its usual procedure number and the addition of modifier 91. note: this modifier may not be used when tests are rerun to confirm initial results; due to testing problems with specimens or equipment; or for any other reason when a normal, one-time, reportable result is all that is required. this modifier may not be used when other code(s) describe a series of test results (eg, glucose tolerance tests, evocative/suppression testing). this modifier may only be used for laboratory test(s) performed more than once on the same day on the same patient.
GA	Waiver of liability statement issued as required by payer policy, individual case
Q4	Service for ordering/referring physician qualifies as a service exemption