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Official Description

Agglutinins, febrile (eg, Brucella, Francisella, Murine typhus, Q fever, Rocky Mountain spotted fever, scrub typhus), each antigen

© Copyright 2026 American Medical Association. All rights reserved.

Common Language Description

The CPT® Code 86000 refers to the laboratory test for agglutinins associated with febrile illnesses, specifically targeting various pathogens that can cause cryptic infections. This test involves analyzing a blood sample to detect the presence of agglutinating antibodies against specific febrile antigens. The term "agglutinin" refers to antibodies that cause particles, such as bacteria, to clump together, which is a key indicator of an immune response to an infection. The test is particularly useful in identifying infections caused by pathogens that may not be immediately recognizable, thus aiding in the diagnosis of febrile illnesses. The procedure is often performed when a patient presents with fever of unknown origin, and it may involve testing for multiple pathogens simultaneously. When multiple antigens are tested, the procedure is commonly referred to as a febrile agglutination profile. Among the pathogens typically included in this testing are Brucella, Francisella, Murine typhus, Q fever, Rocky Mountain spotted fever, and scrub typhus. Additionally, the test can identify certain groups of Salmonella, particularly Salmonella group D 'O' (somatic) antigen and Salmonella groups A, B, and D 'H' (flagellar) antigens. It can also detect specific strains of Proteus vulgaris, including OX-2, OX-K, and OX-19 antigens. The testing methodology employed is direct agglutination (DA), and it is important to note that the code 86000 is reported for each antigen tested, reflecting the comprehensive nature of this diagnostic procedure.

© Copyright 2026 Coding Ahead. All rights reserved.

1. Indications

The CPT® Code 86000 is indicated for use in the evaluation of febrile illnesses where the causative pathogen is not immediately identifiable. The following conditions and symptoms may warrant the use of this test:

  • Fever of Unknown Origin - When a patient presents with a persistent fever without a clear diagnosis, this test can help identify potential underlying infections.
  • Suspected Cryptic Infections - In cases where there is a suspicion of an infection caused by less common pathogens, this test can assist in confirming the presence of specific agglutinins.
  • Evaluation of Specific Pathogens - The test is particularly useful for detecting infections caused by Brucella, Francisella, Murine typhus, Q fever, Rocky Mountain spotted fever, and scrub typhus.
  • Assessment of Opportunistic Infections - The test may also be employed to identify opportunistic infections, such as those caused by Proteus vulgaris, especially in immunocompromised patients.

2. Procedure

The procedure for CPT® Code 86000 involves several key steps to ensure accurate testing for agglutinins against febrile antigens. The following procedural steps are typically followed:

  • Step 1: Sample Collection - A blood sample is collected from the patient, usually via venipuncture. This sample serves as the basis for testing the presence of agglutinating antibodies.
  • Step 2: Preparation of Antigens - Specific antigens corresponding to the pathogens of interest are prepared in the laboratory. These antigens are crucial for the agglutination reaction that will be observed.
  • Step 3: Direct Agglutination Testing - The blood sample is mixed with the prepared antigens in a controlled environment. The presence of agglutinating antibodies will cause visible clumping of the antigens, indicating a positive reaction.
  • Step 4: Interpretation of Results - The results are analyzed to determine which specific antigens have elicited an immune response. Each positive reaction corresponds to the presence of antibodies against a specific pathogen.
  • Step 5: Reporting - The findings are documented, and the code 86000 is reported for each antigen tested, reflecting the comprehensive nature of the evaluation.

3. Post-Procedure

After the procedure associated with CPT® Code 86000, the patient may not require any specific post-procedure care, as the blood sample collection is minimally invasive. However, it is essential to monitor the patient for any adverse reactions, although these are rare. The results of the agglutination test will typically be available within a few days, and healthcare providers should follow up with the patient to discuss the findings and any necessary further actions based on the results. If positive agglutination is detected, additional diagnostic steps may be warranted to confirm the specific infection and guide treatment options.

Short Descr AGGLUTININS FEBRILE ANTIGEN
Medium Descr AGGLUTININS FEBRILE EACH ANTIGEN
Long Descr Agglutinins, febrile (eg, Brucella, Francisella, Murine typhus, Q fever, Rocky Mountain spotted fever, scrub typhus), each antigen
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 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.
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.
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.
Date
Action
Notes
2013-01-01 Changed Short Descriptor changed.
2011-01-01 Changed Short description changed.
Pre-1990 Added Code added.
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Description
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