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Official Description

Antibody; Borrelia burgdorferi (Lyme disease)

© Copyright 2026 American Medical Association. All rights reserved.

Common Language Description

The CPT® Code 86618 refers to a laboratory test specifically designed to measure antibodies against Borrelia burgdorferi, the bacterium responsible for Lyme disease. This test is crucial for diagnosing Lyme disease, particularly in patients exhibiting symptoms consistent with the infection. The test can be performed on serum, which is the liquid portion of blood, or cerebrospinal fluid (CSF), which surrounds the brain and spinal cord. It serves as a first-line screening tool for individuals who either live in or have traveled to areas where black-legged ticks, the vectors for Lyme disease, are prevalent. The accuracy of this test is notably higher when conducted within four weeks following a tick bite, especially if the patient presents with erythema migrans, commonly known as the "bull's eye" rash, which is a hallmark sign of Lyme disease. The presence of C6 peptide antibodies to B. burgdorferi is particularly significant, as it is recognized as a standalone diagnostic marker for Lyme disease. In the early stages of infection, IgM antibodies typically become detectable within 2 to 3 weeks post-exposure, aiding in the diagnosis of early Lyme disease. Conversely, IgG antibodies, which also indicate exposure, do not reach their peak levels until approximately 4 to 6 months after the initial infection. In cases where the C6 peptide antibodies test positive or yield equivocal results, further testing for IgG and IgM antibodies is recommended. Additionally, positive or uncertain results for these antibodies should prompt a reflex to a Western Blot or immunoblot confirmation test to ensure accurate diagnosis. The collection of blood samples for this test is performed through a separately reportable venipuncture, while CSF samples are obtained via a separately reportable lumbar puncture. The testing of both serum and CSF is conducted using a semi-quantitative enzyme-linked immunosorbent assay (ELISA), a widely used laboratory technique for detecting and quantifying proteins, including antibodies.

© Copyright 2026 Coding Ahead. All rights reserved.

1. Indications

The CPT® Code 86618 is indicated for use in the following scenarios:

  • Symptoms of Lyme Disease The test is performed when a patient exhibits symptoms consistent with Lyme disease infection, such as fever, headache, fatigue, and characteristic skin rashes.
  • Exposure to Endemic Areas It is particularly relevant for individuals who live in or have visited regions where black-legged ticks are prevalent, as these areas are known to have a higher incidence of Lyme disease.
  • Timing Post-Tick Bite The test is most reliable when conducted within four weeks of a tick bite, especially if the patient develops erythema migrans, which is a distinctive rash associated with Lyme disease.

2. Procedure

The procedure for conducting the antibody test for Borrelia burgdorferi involves several key steps:

  • Sample Collection A blood sample is obtained through a venipuncture, which is a standard procedure for drawing blood. If cerebrospinal fluid (CSF) is required, it is collected via a lumbar puncture, a procedure that involves inserting a needle into the lower back to access the CSF surrounding the spinal cord.
  • Testing Methodology The collected serum and/or CSF samples are then subjected to a semi-quantitative enzyme-linked immunosorbent assay (ELISA). This laboratory technique is designed to detect and quantify the presence of antibodies specific to Borrelia burgdorferi in the samples.
  • Interpretation of Results Following the ELISA testing, the presence of C6 peptide antibodies is evaluated. A positive result for these antibodies is considered a strong indicator of Lyme disease. If the C6 peptide test yields positive or equivocal results, further testing for IgG and IgM antibodies is performed to confirm the diagnosis.
  • Reflex Testing In cases where the initial antibody tests are positive or uncertain, a reflex to a Western Blot or immunoblot confirmation test is mandated to ensure the accuracy of the diagnosis. This additional testing helps to confirm the presence of Lyme disease by providing more detailed information about the antibodies present in the patient's system.

3. Post-Procedure

After the procedure, patients may be monitored for any immediate complications related to the venipuncture or lumbar puncture, such as bleeding or infection at the site of needle insertion. The results of the antibody tests are typically available within a few days, and healthcare providers will discuss the findings with the patient. If the test results indicate the presence of antibodies consistent with Lyme disease, appropriate treatment options will be considered based on the patient's clinical presentation and history. It is important for patients to follow up with their healthcare provider to discuss the results and any necessary next steps in their care.

Short Descr LYME DISEASE ANTIBODY
Medium Descr ANTIBODY BORRELIA BURGDORFERI LYME DISEASE
Long Descr Antibody; Borrelia burgdorferi (Lyme disease)
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) Yes
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.
59 Distinct procedural service: under certain circumstances, it may be necessary to indicate that a procedure or service was distinct or independent from other non-e/m services performed on the same day. modifier 59 is used to identify procedures/services, other than e/m services, that are not normally reported together, but are appropriate under the circumstances. documentation must support a different session, different procedure or surgery, different site or organ system, separate incision/excision, separate lesion, or separate injury (or area of injury in extensive injuries) not ordinarily encountered or performed on the same day by the same individual. however, when another already established modifier is appropriate it should be used rather than modifier 59. only if no more descriptive modifier is available, and the use of modifier 59 best explains the circumstances, should modifier 59 be used. note: modifier 59 should not be appended to an e/m service. to report a separate and distinct e/m service with a non-e/m service performed on the same date, see modifier 25.
QW Clia waived test
Q4 Service for ordering/referring physician qualifies as a service exemption
XU Unusual non-overlapping service, the use of a service that is distinct because it does not overlap usual components of the main service
GA Waiver of liability statement issued as required by payer policy, individual case
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.
76 Repeat procedure or service by same physician or other qualified health care professional: it may be necessary to indicate that a procedure or service was repeated by the same physician or other qualified health care professional subsequent to the original procedure or service. this circumstance may be reported by adding modifier 76 to the repeated procedure or service. note: this modifier should not be appended to an e/m service.
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.
GV Attending physician not employed or paid under arrangement by the patient's hospice provider
GW Service not related to the hospice patient's terminal condition
GY Item or service statutorily excluded, does not meet the definition of any medicare benefit or, for non-medicare insurers, is not a contract benefit
GZ Item or service expected to be denied as not reasonable and necessary
SA Nurse practitioner rendering service in collaboration with a physician
XE Separate encounter, a service that is distinct because it occurred during a separate encounter
Date
Action
Notes
1993-01-01 Added First appearance in code book in 1993.
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