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Official Description

Antibody; Chlamydia

© Copyright 2026 American Medical Association. All rights reserved.

Common Language Description

The CPT® Code 86631 refers to the laboratory test for antibodies to Chlamydia, a genus of bacteria responsible for various infections in humans. The most notable species within this genus is Chlamydia trachomatis, which is primarily known for causing sexually transmitted diseases (STDs). This particular infection often remains asymptomatic, meaning that individuals may not exhibit any noticeable symptoms. However, if left untreated, it can lead to severe complications, particularly in women, including irreversible damage to the reproductive system, which may result in infertility. In men, while the infection can cause symptoms such as burning and itching in the urethra, they are less likely to experience long-term reproductive issues. In addition to C. trachomatis, the Chlamydia genus includes C. pneumoniae, which is associated with respiratory infections such as pneumonia, bronchitis, rhinitis, and pharyngitis. Another species, C. psittaci, primarily affects birds but can be transmitted to humans through contact with infected birds, leading to flu-like symptoms. Testing for Chlamydia antibodies can be performed using various methods, including the indirect fluorescent antibody test and the enzyme-linked immunosorbent assay (ELISA). The CPT® Code 86631 is specifically designated for screening tests that detect antibodies for all species of Chlamydia and for tests that identify IgG antibodies. For tests that identify IgM antibodies, the CPT® Code 86632 should be used. It is important to note that each species and each immunoglobulin class (IgG, IgM) tested is reported separately, ensuring precise and accurate laboratory results.

© Copyright 2026 Coding Ahead. All rights reserved.

1. Indications

The CPT® Code 86631 is indicated for the testing of antibodies to Chlamydia in various clinical scenarios. The following conditions and situations warrant the use of this test:

  • Asymptomatic Screening Individuals who are at risk for Chlamydia infections, particularly sexually active individuals, may undergo screening even in the absence of symptoms to prevent potential complications.
  • Infertility Evaluation Women experiencing infertility may be tested for Chlamydia antibodies to determine if a past infection has contributed to reproductive issues.
  • Symptomatic Patients Patients presenting with symptoms suggestive of Chlamydia infection, such as urethral burning or discharge in men, or pelvic pain in women, may be tested to confirm the diagnosis.
  • Pregnancy Screening Pregnant women are often screened for Chlamydia to reduce the risk of transmission to the newborn and to prevent complications during pregnancy.
  • Follow-Up Testing Individuals who have previously tested positive for Chlamydia may require follow-up testing to confirm the resolution of the infection after treatment.

2. Procedure

The procedure for testing antibodies to Chlamydia using CPT® Code 86631 involves several key steps, which are outlined below:

  • Step 1: Sample Collection A blood sample is collected from the patient, typically via venipuncture. This sample serves as the basis for the antibody testing.
  • Step 2: Laboratory Processing The collected blood sample is sent to a laboratory where it undergoes processing. This may involve separating the serum from the blood cells to prepare it for testing.
  • Step 3: Antibody Testing The laboratory performs the antibody test using methods such as the indirect fluorescent antibody test or enzyme-linked immunosorbent assay (ELISA). These methods detect the presence of IgG antibodies specific to Chlamydia.
  • Step 4: Result Interpretation Once the testing is complete, the laboratory interprets the results. A positive result indicates the presence of antibodies to Chlamydia, suggesting a past or current infection, while a negative result indicates no detectable antibodies.
  • Step 5: Reporting The results are documented and reported to the healthcare provider, who will discuss the findings with the patient and determine any necessary follow-up actions or treatments.

3. Post-Procedure

After the antibody testing for Chlamydia using CPT® Code 86631, patients may receive specific instructions based on their results. If the test is positive, healthcare providers may recommend further diagnostic testing, treatment options, and counseling regarding safe sexual practices to prevent reinfection. In cases where the test is negative, providers may still discuss the importance of regular screenings, especially for individuals at high risk. Additionally, patients should be informed about the potential for false negatives and the importance of follow-up testing if symptoms persist or if there is a high suspicion of infection despite negative results. Overall, post-procedure care focuses on ensuring patient understanding and addressing any ongoing health concerns related to Chlamydia infections.

Short Descr CHLAMYDIA ANTIBODY
Medium Descr ANTIBODY CHLAMYDIA
Long Descr Antibody; Chlamydia
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 Service Paid under Fee Schedule or Payment System other than OPPS
Type of Service (TOS) 5 - Diagnostic Laboratory
Berenson-Eggers TOS (BETOS) T1H - Lab tests - other (non-Medicare fee schedule)
MUE 6
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.
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
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.
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.
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.
G8 Monitored anesthesia care (mac) for deep complex, complicated, or markedly invasive surgical procedure
GW Service not related to the hospice patient's terminal condition
GZ Item or service expected to be denied as not reasonable and necessary
Date
Action
Notes
1993-01-01 Added First appearance in code book in 1993.
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