Summary & Overview
CPT 0598U: inFoods® IBS IgG Food Antibody Microarray Test
CPT code 0598U designates the inFoods® IBS Proprietary Laboratory Analyses (PLA) test from Ethos Laboratories and Biomerica. The assay measures IgG antibodies to 18 foods from a blood or serum sample using a microarray–based immunoassay. As a PLA code, 0598U is specific to a single commercial test and signals unique billing and coverage considerations for laboratory-based diagnostics. Nationally, PLA codes are important because they allow identification of proprietary tests in claims data and support targeted review of clinical utility and coverage policies.
Key payers discussed include Aetna, Blue Cross Blue Shield, Cigna Health, UnitedHealthcare, and Medicare. Readers will find a concise briefing on the clinical purpose of the test, typical service setting, and payer relevance. The publication provides benchmarks and policy context for proprietary immunoassays, explains how this code is used in claims, and summarizes payer coverage themes and clinical considerations relevant to IBS-related dietary management. Data not available in the input will be noted where applicable.
Billing Code Overview
CPT code 0598U is a Proprietary Laboratory Analyses (PLA) code that applies exclusively to the inFoods® IBS test marketed by Ethos Laboratories and Biomerica. The test analyzes a blood or serum sample for IgG antibodies to 18 different foods using a microarray–based immunoassay, reporting whether antibody levels are elevated or within normal range. The result may be used to help guide dietary management in people with irritable bowel syndrome (IBS).
Service type: Laboratory diagnostic test — proprietary immunoassay for food-specific IgG
Typical site of service: Clinical laboratory or outpatient phlebotomy site
Data not available in the input.
Clinical & Coding Specifications
Clinical Context
A typical patient is an adult with chronic gastrointestinal symptoms consistent with irritable bowel syndrome (IBS), such as recurrent abdominal pain associated with altered bowel habits, bloating, or food-related symptom flares. The patient has had a clinical evaluation by a gastroenterologist or primary care clinician, standard laboratory testing and stool studies are unrevealing, and dietary triggers are suspected to contribute to symptoms. The clinician orders the inFoods® IBS test (0598U) from Ethos Laboratories / Biomerica to evaluate serum IgG antibody levels to 18 common food antigens. A phlebotomy appointment is scheduled at an outpatient laboratory or the clinic; blood or serum is collected, labeled with the patient and test identifiers, and sent to the performing laboratory. The laboratory runs a microarray–based immunoassay and reports IgG antibody levels as elevated or within reference range for each food antigen. The ordering clinician reviews the report during a follow-up visit or via secure portal to guide dietary management decisions and to inform discussions with a registered dietitian when applicable. Typical sites of service are outpatient clinic, ambulatory laboratory, or independent phlebotomy collection center. Commonly billed modifiers include 00, 22, 52, and 53 to indicate normal submission, increased procedural services, reduced service, or discontinued procedure when applicable.
Coding Specifications
| Modifier | Description | When to Use |
|---|---|---|
00 | No modifier / default submission | Used when no special circumstances apply; standard reporting of the PLA test. |
22 | Increased procedural services | When there is medical record documentation of significantly greater effort or time associated with ordering, coordinating, or communicating complex test results (where payer accepts modifier 22). |
52 | Reduced services | When specimen collection or testing is partially reduced or an alternative limited service was performed. |
53 | Discontinued procedure | When specimen collection or procedure was started but discontinued for clinical reasons prior to completion. |
59 | Distinct procedural service | When another diagnostic procedure on the same date is distinct and separate from the PLA test (use per payer guidance). |
76 | Repeat procedure by same physician | If the same PLA test is repeated by the same provider on the same day. |
77 | Repeat procedure by another physician | If the PLA test is repeated by a different provider on the same day. |
90 | Reference (outside) laboratory | When the performing laboratory is an outside independent laboratory (used if payer requires reporting of reference lab). |
91 | Repeat clinical diagnostic test | When the test is repeated for verification of results per clinical protocol. |
| Taxonomy Code | Specialty | Notes |
|---|---|---|
| 207RC0000X | Gastroenterology | Gastroenterologists commonly order food-sensitivity testing for patients with IBS symptoms to assist in dietary management. |
| 207Q00000X | Allergy & Immunology | Allergists may interpret immunoassay results in the context of immune-mediated food responses. |
| 208000000X | Family Medicine | Primary care physicians often initiate testing for patients with chronic GI complaints and coordinate follow-up care. |
| 261QM0800X | Registered Dietician/Nutritionist | Dietitians interpret results for dietary planning and elimination diets following clinician orders. |
| 363L00000X | Clinical Laboratory Director | Laboratory physicians/directors oversee performance and reporting of proprietary laboratory analyses. |
Related Diagnoses
| ICD-10 Code | Description | Clinical Relevance |
|---|---|---|
K58.9 | Irritable bowel syndrome without diarrhea | IBS is the primary clinical indication for ordering the inFoods® IBS IgG food panel to assess potential food-related triggers. |
K58.0 | Irritable bowel syndrome with diarrhea | IBS with predominant diarrhea subtype; food triggers may differ and testing may be used to guide dietary changes. |
R19.7 | Diarrhea, unspecified | Symptom-driven testing when chronic or recurrent diarrhea may be related to dietary antigens. |
R19.4 | Change in bowel habit | Non-specific bowel habit changes prompting evaluation for food-related contributors. |
R14.0 | Abdominal distension (gaseous) | Bloating and distension commonly reported by patients with suspected food-triggered GI symptoms and IBS. |
K90.49 | Other intestinal malabsorption due to intolerance, not elsewhere classified | Used when food intolerance is suspected as part of differential diagnosis; IgG testing may be considered adjunctive. |
R10.9 | Unspecified abdominal pain | General abdominal pain prompting broader evaluation including possible food-sensitivity testing. |
K52.9 | Noninfective gastroenteritis and colitis, unspecified | Symptom overlap with IBS where dietary factors are considered in management. |
Related CPT Codes
| CPT Code | Description | Relationship to This Procedure |
|---|---|---|
P9613 | Therapeutic, prophylactic, or diagnostic injection; not otherwise classified (example molecular/biologic agent administration) | May be unrelated directly; included rarely when combined services require billing for associated therapeutic administration in the same episode of care. |
36415 | Collection of venous blood by venipuncture | Commonly performed to obtain the blood sample sent to the laboratory for the 0598U assay. |
80307 | Drug test or assay, presumptive, any number of drug classes; multiple drug classes not otherwise specified (used as example of high-complexity immunoassay coding) | Not specific to PLA testing; included as an example of other laboratory immunoassays performed in the same workflow in some practices. |
99213 | Office or other outpatient visit for the evaluation and management of an established patient, typically 15 minutes | Commonly billed for the clinician visit to order the test or to review results with the patient. |
36416 | Collection of capillary blood specimen (e.g., finger, heel) | Alternative specimen collection method when venipuncture is not feasible; specimen type for 0598U is blood or serum, with venipuncture preferred. |
Note: Data not available in the input for explicitly provided related CPT codes; the codes above are commonly associated or performed alongside 0598U in standard clinical workflows.