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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; cryptosporidium

© Copyright 2026 American Medical Association. All rights reserved.

Common Language Description

The CPT® Code 87328 refers to a laboratory test designed to detect the presence of cryptosporidium antigen in a fecal sample using various immunoassay techniques. Cryptosporidium is a microscopic, one-celled parasite responsible for the diarrheal illness known as cryptosporidiosis. This parasite invades the intestinal walls, leading to symptoms such as watery diarrhea, dehydration, loss of appetite, weight loss, and abdominal cramps, which can persist for several weeks and may recur sporadically. The test can be performed using several immunoassay methods, including enzyme immunoassay (EIA), enzyme-linked immunosorbent assay (ELISA), fluorescence immunoassay (FIA), and immunochemiluminometric assay (IMCA). Each of these techniques operates on the principle of detecting specific antigens by utilizing antibodies that bind to the target antigen. The EIA and ELISA methods are particularly sensitive, capable of identifying minute quantities of the antigen through a colorimetric reaction that occurs when a secondary enzyme-labeled antibody is introduced. This reaction results in a visible color change, which can be quantitatively assessed. The FIA method employs a fluorescent compound to detect the binding of the antibody to the antigen, while the IMCA method utilizes chemiluminescent substances to measure the light emitted from the antigen-antibody complex. Overall, this test is crucial for diagnosing cryptosporidiosis and guiding appropriate treatment options.

© Copyright 2026 Coding Ahead. All rights reserved.

1. Indications

The procedure associated with CPT® Code 87328 is indicated for the detection of cryptosporidium antigen in patients who present with symptoms consistent with cryptosporidiosis. These symptoms may include:

  • Watery Diarrhea A common symptom of cryptosporidiosis, characterized by frequent, loose, and watery stools.
  • Dehydration Resulting from excessive fluid loss due to diarrhea, leading to symptoms such as dry mouth, decreased urine output, and fatigue.
  • Lack of Appetite Often observed in patients suffering from gastrointestinal distress.
  • Weight Loss Can occur due to prolonged diarrhea and inadequate nutrient absorption.
  • Stomach Cramps Abdominal pain or discomfort that may accompany diarrhea.

2. Procedure

The procedure for detecting cryptosporidium antigen using CPT® Code 87328 involves several key steps, which are outlined below:

  • Sample Collection A fecal sample is collected from the patient, which may be placed in a fixative or sent fresh to the laboratory for analysis. Proper collection and handling of the sample are crucial to ensure accurate test results.
  • Preparation of the Sample The fecal sample is processed in the laboratory to extract the antigen. This may involve homogenizing the sample and preparing it for the specific immunoassay technique being utilized.
  • Immunoassay Technique The laboratory technician employs one of the immunoassay methods—EIA, ELISA, FIA, or IMCA—to detect the presence of cryptosporidium antigen. Each method involves adding specific antibodies that bind to the antigen, followed by the introduction of a detection reagent that produces a measurable signal, such as a color change or fluorescence.
  • Result Interpretation The results of the immunoassay are assessed qualitatively or semi-quantitatively. A colorimetric reading or fluorescence measurement is taken to determine the presence and concentration of the antigen in the sample.

3. Post-Procedure

After the procedure, the laboratory will provide a report detailing the presence or absence of cryptosporidium antigen in the fecal sample. If the test is positive, further clinical evaluation and management may be necessary to address the patient's symptoms and provide appropriate treatment. It is important for healthcare providers to discuss the results with the patient and consider any additional diagnostic testing or therapeutic interventions that may be warranted based on the findings.

Short Descr CRYPTOSPORIDIUM AG IA
Medium Descr IAAD IA CRYPTOSPORIDIUM
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; cryptosporidium
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.
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.
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.
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.
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
XU Unusual non-overlapping service, the use of a service that is distinct because it does not overlap usual components of the main service
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 changed.
2016-01-01 Changed Description Changed
2011-01-01 Changed Short description changed.
2007-01-01 Changed Code description changed.
2004-01-01 Changed Code description changed.
1998-01-01 Added First appearance in code book in 1998.
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Description
Code
Description
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