Summary & Overview

CPT 0558U: IGoCheck™ BF7 ELISA for Colorectal Cancer Monitoring

CPT code 0558U is a Proprietary Laboratory Analyses (PLA) code assigned specifically to IGoCheck™, a blood-based ELISA that quantifies the BF7 antigen to monitor colorectal cancer response to therapy. As a PLA code, 0558U applies only to the single manufacturer and test indicated, which matters for coverage, billing clarity, and claims processing nationwide. Its designation signals a unique, proprietary diagnostic tool rather than a generic assay.

Major national payers considered in this analysis include Aetna, Blue Cross Blue Shield, Cigna Health, UnitedHealthcare, and Medicare. Readers will find an overview of clinical context for serial biomarker monitoring in colorectal cancer, the laboratory service setting and typical use cases for this ELISA, and practical billing considerations tied to a PLA code. The publication summarizes benchmark information where available, outlines payer coverage themes, and flags policy or coding issues relevant to proprietary laboratory tests. It is intended to inform clinical program managers, laboratory billing teams, and policy analysts about the clinical purpose of the test, payer landscape, and the types of documentation and coding attention PLA codes commonly require.

Data not available in the input for specific modifiers, taxonomies, ICD-10 pairings, and related codes.

AetnaBlue Cross Blue ShieldCigna HealthUnitedHealthcareMedicare0558UCPTProprietary Laboratory AnalysesPLAcolorectal cancerBF7 antigenELISAlaboratory billingoncology monitoring

Billing Code Overview

CPT code 0558U is a Proprietary Laboratory Analyses (PLA) code for the IGoCheck™ test from Milagen Inc. The test is a blood-based enzyme-linked immunosorbent assay (ELISA) that measures the BF7 antigen protein level in patient serum. Results are used to assess colorectal cancer response to therapy and to detect signs of progression or regression.

Service type: Laboratory biomarker assay for oncology monitoring
Typical site of service: Clinical laboratory or hospital laboratory with blood draw performed in an outpatient clinic, phlebotomy center, or hospital outpatient setting

Data not available in the input.

Clinical & Coding Specifications

Clinical Context

A 62-year-old patient with a history of stage II colorectal adenocarcinoma undergoing systemic therapy presents for routine surveillance. The oncology clinic orders the proprietary blood-based assay IGoCheck™ (0558U) to measure serum BF7 antigen levels via ELISA to assess tumor response to current therapy and to detect biochemical signs of progression. A venipuncture is performed in the outpatient oncology infusion center or hospital outpatient lab; serum is processed per the test kit instructions and sent to Milagen Inc. (or the designated performing laboratory). Results are reported as quantitative BF7 antigen concentration with interpretive comments indicating rising, stable, or falling levels to inform the treating oncologist’s assessment of response to therapy. Typical workflow steps: order placed by oncologist, specimen collection in outpatient infusion center or clinical laboratory, specimen processing and shipment to the performing lab, assay run by the proprietary laboratory, and report routed back to the ordering provider for integration into treatment planning.

Coding Specifications

Modifier	Description	When to Use
`00`	Default/No modifier	Use when no specific reporting modifier is applicable and full service is provided.
`22`	Increased procedural services	Use when documentation supports substantially greater effort or work than typical for the test (rare for PLA tests; apply only with justification).
`52`	Reduced services	Use if the assay was partially performed or limited (for example, inadequate specimen leading to partial testing).
`53`	Discontinued procedure	Use when testing was started but discontinued prior to completion and no valid result was produced.
`59`	Distinct procedural service	Use if another distinct laboratory service was performed the same day and must be distinguished (apply cautiously for labs).
`76`	Repeat procedure by same physician/lab	Use when the identical assay is repeated by the same ordering provider/performing lab on the same day.
`77`	Repeat procedure by another physician/lab	Use when the identical assay is repeated by a different performing laboratory.
`90`	Reference (Outside) laboratory	Use when the performing lab is an outside reference lab distinct from the billing entity.
`91`	Repeat clinical diagnostic laboratory test	Use when the same test is repeated on the same specimen to verify results.

Taxonomy Code	Specialty	Notes
207R00000X	Medical Oncology	Ordering and interpreting clinicians who frequently request tumor response biomarkers.
207L00000X	Hematology & Oncology	Specialists managing systemic cancer therapy and surveillance.
207Q00000X	Surgical Oncology	May order tests for post-operative surveillance in collaboration with medical oncology.
2080P0003X	Clinical Pathology	Laboratory directors and clinical pathologists overseeing assay validation and reporting.
363LF0000X	Laboratory Director	Individuals responsible for laboratory operations and compliance with PLA test performance.

Related Diagnoses

ICD-10 Code	Description	Clinical Relevance
`C18.9`	Malignant neoplasm of colon, unspecified	Primary colorectal cancer diagnosis for which BF7 antigen surveillance may be used to monitor response or recurrence.
`C19`	Malignant neoplasm of rectosigmoid junction	Colorectal primary site where serum tumor markers may assist in monitoring treatment effect.
`C20`	Malignant neoplasm of rectum	Common indication for postoperative and therapy response surveillance using tumor markers.
`Z85.038`	Personal history of malignant neoplasm of large intestine	Patients with prior colorectal cancer may receive periodic tumor marker testing for recurrence surveillance.
`R91.8`	Other nonspecific abnormal findings of lung field (placeholder for metastatic workup relevance)	Used when surveillance includes evaluation for metastatic disease; tumor markers can trigger further imaging.
`R97.1`	Elevated tumor markers, other than PSA	Symptom/observation code used when an elevated tumor marker prompts clinical action or monitoring.

Related CPT Codes

CPT Code	Description	Relationship to This Procedure
`36415`	Collection of venous blood by venipuncture	Venous blood collection commonly performed prior to sending serum for the `0558U` assay.
`80053`	Comprehensive metabolic panel	Routine concurrent chemistry testing often ordered alongside tumor marker monitoring for overall clinical assessment.
`86304`	Antibody; qualitative or semi-quantitative	Represents immunoassay methodology; `0558U` uses ELISA immunoassay techniques for BF7 antigen measurement (note: `0558U` is a PLA code for the specific proprietary assay).
`88360`	Immunohistochemistry; initial single antibody stain	May be used in tissue-based correlated testing when tissue pathology is re-evaluated in parallel with serum markers.
`G0338`	Oncology care coordination (example of supportive services)	Represents related oncology management services that contextualize laboratory surveillance results in care planning.

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Summary & Overview

CPT 0558U: IGoCheck™ BF7 ELISA for Colorectal Cancer Monitoring

Data not available in the input for specific modifiers, taxonomies, ICD-10 pairings, and related codes.

AetnaBlue Cross Blue ShieldCigna HealthUnitedHealthcareMedicare0558UCPTProprietary Laboratory AnalysesPLAcolorectal cancerBF7 antigenELISAlaboratory billingoncology monitoring

Billing Code Overview

Service type: Laboratory biomarker assay for oncology monitoring
Typical site of service: Clinical laboratory or hospital laboratory with blood draw performed in an outpatient clinic, phlebotomy center, or hospital outpatient setting

Data not available in the input.

Clinical & Coding Specifications

Clinical Context

Coding Specifications

Modifier	Description	When to Use
`00`	Default/No modifier	Use when no specific reporting modifier is applicable and full service is provided.
`22`	Increased procedural services	Use when documentation supports substantially greater effort or work than typical for the test (rare for PLA tests; apply only with justification).
`52`	Reduced services	Use if the assay was partially performed or limited (for example, inadequate specimen leading to partial testing).
`53`	Discontinued procedure	Use when testing was started but discontinued prior to completion and no valid result was produced.
`59`	Distinct procedural service	Use if another distinct laboratory service was performed the same day and must be distinguished (apply cautiously for labs).
`76`	Repeat procedure by same physician/lab	Use when the identical assay is repeated by the same ordering provider/performing lab on the same day.
`77`	Repeat procedure by another physician/lab	Use when the identical assay is repeated by a different performing laboratory.
`90`	Reference (Outside) laboratory	Use when the performing lab is an outside reference lab distinct from the billing entity.
`91`	Repeat clinical diagnostic laboratory test	Use when the same test is repeated on the same specimen to verify results.

Taxonomy Code	Specialty	Notes
207R00000X	Medical Oncology	Ordering and interpreting clinicians who frequently request tumor response biomarkers.
207L00000X	Hematology & Oncology	Specialists managing systemic cancer therapy and surveillance.
207Q00000X	Surgical Oncology	May order tests for post-operative surveillance in collaboration with medical oncology.
2080P0003X	Clinical Pathology	Laboratory directors and clinical pathologists overseeing assay validation and reporting.
363LF0000X	Laboratory Director	Individuals responsible for laboratory operations and compliance with PLA test performance.

Related Diagnoses

ICD-10 Code	Description	Clinical Relevance
`C18.9`	Malignant neoplasm of colon, unspecified	Primary colorectal cancer diagnosis for which BF7 antigen surveillance may be used to monitor response or recurrence.
`C19`	Malignant neoplasm of rectosigmoid junction	Colorectal primary site where serum tumor markers may assist in monitoring treatment effect.
`C20`	Malignant neoplasm of rectum	Common indication for postoperative and therapy response surveillance using tumor markers.
`Z85.038`	Personal history of malignant neoplasm of large intestine	Patients with prior colorectal cancer may receive periodic tumor marker testing for recurrence surveillance.
`R91.8`	Other nonspecific abnormal findings of lung field (placeholder for metastatic workup relevance)	Used when surveillance includes evaluation for metastatic disease; tumor markers can trigger further imaging.
`R97.1`	Elevated tumor markers, other than PSA	Symptom/observation code used when an elevated tumor marker prompts clinical action or monitoring.

Related CPT Codes

CPT Code	Description	Relationship to This Procedure
`36415`	Collection of venous blood by venipuncture	Venous blood collection commonly performed prior to sending serum for the `0558U` assay.
`80053`	Comprehensive metabolic panel	Routine concurrent chemistry testing often ordered alongside tumor marker monitoring for overall clinical assessment.
`86304`	Antibody; qualitative or semi-quantitative	Represents immunoassay methodology; `0558U` uses ELISA immunoassay techniques for BF7 antigen measurement (note: `0558U` is a PLA code for the specific proprietary assay).
`88360`	Immunohistochemistry; initial single antibody stain	May be used in tissue-based correlated testing when tissue pathology is re-evaluated in parallel with serum markers.
`G0338`	Oncology care coordination (example of supportive services)	Represents related oncology management services that contextualize laboratory surveillance results in care planning.