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Official Description

Infectious agent antigen detection by immunoassay technique, (eg, enzyme immunoassay [EIA], enzyme-linked immunosorbent assay [ELISA], fluorescence immunoassay [FIA], immunochemiluminometric assay [IMCA]) qualitative or semiquantitative; Shiga-like toxin

© Copyright 2026 American Medical Association. All rights reserved.

Common Language Description

The CPT® Code 87427 refers to a laboratory test that detects the presence of Shiga-like toxin antigen using various immunoassay techniques. This test is particularly significant in identifying infections caused by specific strains of Escherichia coli (E. coli), such as E. coli O157, O26, O111, and O103, which are known to produce Shiga-like toxins. These toxins can lead to severe gastrointestinal conditions, including hemorrhagic colitis and hemolytic uremic syndrome, which can be life-threatening. The infection typically occurs through the consumption of contaminated food or water, and it can also spread from person to person through contact with contaminated feces. The procedure involves obtaining a fecal sample, which may be preserved in a fixative or sent fresh to the laboratory for analysis. The immunoassay techniques employed in this test include enzyme immunoassay (EIA), enzyme-linked immunosorbent assay (ELISA), fluorescence immunoassay (FIA), and immunochemiluminometric assay (IMCA). Each of these methods utilizes specific antibodies that bind to the Shiga-like toxin antigen, allowing for the detection of even minute quantities of the toxin. The EIA and ELISA methods produce a color change or fluorescence as a result of a chromogenic reaction, which can be quantitatively assessed. The FIA method employs a fluorescent compound to indicate the presence of the antigen, while the IMCA method utilizes chemiluminescent substances to measure the antigen-antibody complex through light emission. Overall, this test is crucial for diagnosing infections associated with Shiga-like toxins and guiding appropriate clinical management.

© Copyright 2026 Coding Ahead. All rights reserved.

1. Indications

The CPT® Code 87427 is indicated for the detection of Shiga-like toxin antigen in patients who may be experiencing gastrointestinal symptoms associated with infections from specific strains of E. coli. The following conditions and symptoms warrant the performance of this test:

  • Hemorrhagic Colitis - A severe form of colitis characterized by abdominal pain and bloody diarrhea, often associated with E. coli infections.
  • Hemolytic Uremic Syndrome - A serious condition that can occur following an E. coli infection, leading to kidney failure and other complications.
  • Fever - A common symptom that may accompany gastrointestinal infections.
  • Nausea/Vomiting - Symptoms that may indicate an underlying infection affecting the gastrointestinal tract.
  • Abdominal Cramps - Discomfort or pain in the abdominal area, often associated with gastrointestinal disturbances.
  • Bloody Diarrhea - A critical symptom that suggests a severe infection, particularly with Shiga-like toxin-producing E. coli.

2. Procedure

The procedure for CPT® Code 87427 involves several key steps to ensure accurate detection of the Shiga-like toxin antigen:

  • Sample Collection - A fecal sample is obtained from the patient, which may be collected in a fixative to preserve the integrity of the specimen or sent fresh to the laboratory for immediate processing.
  • Preparation of the Sample - The laboratory prepares the fecal sample for testing, ensuring that it is suitable for the immunoassay techniques to be employed.
  • Immunoassay Technique Application - The laboratory utilizes one of the immunoassay techniques, such as enzyme immunoassay (EIA), enzyme-linked immunosorbent assay (ELISA), fluorescence immunoassay (FIA), or immunochemiluminometric assay (IMCA), to detect the presence of the Shiga-like toxin antigen in the sample.
  • Detection and Measurement - The specific immunoassay method will involve adding a secondary, enzyme-labeled antibody to the sample. A chromogenic reaction occurs, producing a visible color change or fluorescence, which indicates the presence of the antigen. The results are assessed qualitatively or semi-quantitatively based on the intensity of the color or fluorescence.
  • Result Interpretation - The laboratory interprets the results, determining whether the Shiga-like toxin antigen is present in the sample, and prepares a report for the healthcare provider.

3. Post-Procedure

After the procedure associated with CPT® Code 87427, the healthcare provider will review the laboratory results to determine the presence of Shiga-like toxin antigen. If the test is positive, appropriate clinical management will be initiated, which may include further diagnostic testing, treatment options, and patient education regarding infection control measures to prevent transmission. Patients may be monitored for symptoms and complications associated with E. coli infections, such as dehydration or kidney function impairment. Follow-up care may be necessary to ensure recovery and address any ongoing health concerns.

Short Descr SHIGA-LIKE TOXIN AG IA
Medium Descr IAAD IA SHIGA-LIKE TOXIN
Long Descr Infectious agent antigen detection by immunoassay technique (eg, enzyme immunoassay [EIA], enzyme-linked immunosorbent assay [ELISA], fluorescence immunoassay [FIA], immunochemiluminometric assay [IMCA]), qualitative or semiquantitative; Shiga-like toxin
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 206 - Microscopic examination (bacterial smear, culture, toxicology)
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.
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.
Q4 Service for ordering/referring physician qualifies as a service exemption
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.
XU Unusual non-overlapping service, the use of a service that is distinct because it does not overlap usual components of the main service
XS Separate structure, a service that is distinct because it was performed on a separate organ/structure
51 Multiple procedures: when multiple procedures, other than e/m services, physical medicine and rehabilitation services or provision of supplies (eg, vaccines), are performed at the same session by the same individual, the primary procedure or service may be reported as listed. the additional procedure(s) or service(s) may be identified by appending modifier 51 to the additional procedure or service code(s). note: this modifier should not be appended to designated "add-on" codes (see appendix d).
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.
CR Catastrophe/disaster related
GA Waiver of liability statement issued as required by payer policy, individual case
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
Q6 Service furnished under a fee-for-time compensation arrangement by a substitute physician or by a substitute physical therapist furnishing outpatient physical therapy services in a health professional shortage area, a medically underserved area, or a rural area
X5 Diagnostic services requested by another clinician: for reporting services by a clinician who furnishes care to the patient only as requested by another clinician or subsequent and related services requested by another clinician; this modifier is reported for patient relationships that may not be adequately captured by the above alternative categories; reporting clinician service examples include but are not limited to, the radiologist's interpretation of an imaging study requested by another clinician
Date
Action
Notes
2022-01-01 Changed First appearance of change in codebook.
2022-01-01 Note Grammatical correction.
2021-01-01 Changed First appearance of change in CPT® Code Set.
2020-10-06 Changed Code description changed.
2016-01-01 Changed Description Changed
2011-01-01 Changed Short description changed.
2007-01-01 Changed Code description changed.
2001-01-01 Added First appearance in code book in 2001.
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