Summary & Overview
CPT 83993: Fecal Calprotectin Test by ELISA
CPT code 83993 denotes a lab-performed immunoassay that measures fecal calprotectin, used to help differentiate inflammatory bowel disease (IBD) from noninflammatory conditions such as irritable bowel syndrome (IBS). This laboratory procedure is clinically important because it provides a noninvasive marker of intestinal inflammation that can reduce reliance on endoscopy for initial triage and monitoring. National payers increasingly consider such assays in diagnostic pathways and coverage policies, influencing utilization and access.
Key payers covered in this analysis include Aetna, Blue Cross Blue Shield, Cigna Health, UnitedHealthcare, and Medicare. Readers will find a concise overview of clinical context and service setting, typical billing and coding considerations, and what to look for in payer coverage policies. The summary highlights practice implications for clinicians ordering the test and for laboratory providers submitting claims, including where to seek payer-specific medical necessity criteria and documentation requirements.
This publication does not provide clinical recommendations but supplies the coding and service context needed to understand how CPT code 83993 fits into diagnostic workflows, reimbursement discussions, and policy updates at the national level.
Billing Code Overview
CPT code 83993 describes a laboratory test that measures fecal calprotectin levels from a small stool sample, typically performed using an enzyme-linked immunosorbent assay (ELISA). The test quantifies intestinal inflammation by detecting calprotectin, a neutrophil-derived protein that rises with mucosal inflammation.
Service Type: Clinical laboratory testing — immunoassay for fecal calprotectin
Typical Site of Service: Clinical laboratory or hospital laboratory
Clinical & Coding Specifications
Clinical Context
A typical patient is an adult or adolescent presenting to gastroenterology or primary care with chronic abdominal pain, persistent diarrhea, weight loss, or blood in the stool. The clinician suspects inflammatory bowel disease (Crohn disease or ulcerative colitis) versus irritable bowel syndrome and orders a fecal calprotectin test to assess intestinal inflammation. The patient collects a small stool sample at home using a provided kit and returns it to the clinic or sends it to a central laboratory. In the laboratory, a medical technologist or lab analyst performs the technical assay, commonly an enzyme-linked immunosorbent assay (ELISA), to quantify fecal calprotectin. Results are reported to the ordering clinician, who integrates the value with clinical history, imaging, and endoscopy findings to guide decisions about further diagnostic testing (such as colonoscopy) or medical management. Typical sites of service include outpatient clinics, ambulatory surgical centers for specimen drop-off, and independent or hospital clinical laboratories. Specimen handling and chain-of-custody documentation are part of the laboratory workflow, and the report includes reference ranges and interpretive comments about levels suggestive of active intestinal inflammation versus noninflammatory causes such as irritable bowel syndrome.
Coding Specifications
| Modifier | Description | When to Use |
|---|---|---|
26 | Professional component | When billing only the professional interpretation component if applicable (rare for this purely technical lab test). |