Summary & Overview
CPT 0088U: Molecular Microscope MMDx–Kidney Assay for Transplant Risk
CPT code 0088U designates a Proprietary Laboratory Analyses (PLA) test: the Molecular Microscope® MMDx–Kidney assay from Kashi Clinical Laboratories. The test analyzes expression of 1,494 genes in transplanted kidney biopsy tissue and compares the pattern to a large reference library to determine risk of transplant organ failure. This molecular diagnostic represents an advanced tool for assessing rejection and graft prognosis and is nationally relevant as precision diagnostics expand in transplant care.
Key payers included in the analysis are Aetna, Blue Cross Blue Shield, Cigna Health, UnitedHealthcare, and Medicare. Readers will find an overview of payer coverage patterns and common modifiers used with the code, plus clinical context on how the assay functions in transplant evaluation. The report outlines benchmarks for utilization and coding practice where available, summarizes policy implications for laboratory reimbursement under PLA coding, and highlights clinical circumstances in which the test is applied.
The content is intended for administrators, coding professionals, and clinicians who need a concise national summary of CPT code 0088U, including what the code represents, where it is performed, and the types of policy and billing considerations that typically accompany proprietary molecular diagnostics.
Billing Code Overview
CPT code 0088U is a Proprietary Laboratory Analyses (PLA) code that specifically identifies the Molecular Microscope® MMDx–Kidney test from Kashi Clinical Laboratories. The test evaluates expression across 1,494 genes in transplanted kidney biopsy tissue and compares results to a proprietary reference library to assess risk of transplant organ failure.
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Service type: Molecular diagnostic laboratory test for transplant pathology
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Typical site of service: Clinical laboratory or specialized transplant diagnostic laboratory (performed on kidney biopsy tissue)
Clinical & Coding Specifications
Clinical Context
A 52-year-old male with a history of end-stage renal disease underwent a deceased donor kidney transplant 18 months ago. He presents to the transplant clinic with rising serum creatinine and new-onset proteinuria. The transplant nephrologist orders the Molecular Microscope® MMDx–Kidney test (0088U) on a core needle transplant kidney biopsy specimen to evaluate molecular signatures associated with rejection and risk of graft failure. Tissue is obtained in the interventional radiology or outpatient procedure unit, submitted to the hospital pathology lab for processing and then sent to Kashi Clinical Laboratories per the manufacturer’s instructions. Results comparing expression across 1,494 genes against the reference library are returned to the transplant team to support diagnosis of antibody-mediated rejection, T-cell–mediated rejection, or nonimmune injury and to inform surveillance and management decisions.
Coding Specifications
| Modifier | Description | When to Use |
|---|---|---|
26 | Professional component | Use when billing provider reports only the professional interpretation portion of the test (rare for PLA tests if separate billing occurs) |
TC | Technical component | Use when billing only the technical component (laboratory processing/shipment) and professional component is billed separately |
52 | Reduced services | Use when the test was partially completed or limited by inadequate tissue, but still produced a report |
53 | Discontinued procedure | Use if the biopsy could not be completed and the lab test was not performed |
59 | Separated service | (Not in provided list) Data not available in the input. |
91 | Repeat clinical diagnostic laboratory test | (Not in provided list) Data not available in the input. |
QK | Qualified nonphysician laboratory director performing test interpretation | Use when a qualified nonphysician laboratory director provides interpretive services for the test |
QX | CLIA waived test performer is different from billing practitioner | Use if a CLIA-waived lab performer was different from the billing provider (unlikely for PLA) |
QY | Laboratory director services under CLIA provider-performed microscopy (PPM) | Use when laboratory director meets PPM reporting requirements |
AD | Anesthesia service by a different physician | Use if anesthesia was performed by a different anesthesiologist (applies to biopsy procedure rather than the PLA test) |
AS | Physician assistant, nurse practitioner, or clinical nurse specialist services | Use when these practitioners perform qualifying services related to specimen collection |
CO | Out-of-state physician providing services | Use when a nonresident physician bills from a different state (rare) |
QK | Qualified nonphysician laboratory director (duplicate entry in list) | Use as above when applicable |
| Taxonomy Code | Specialty | Notes |
|---|---|---|
207RC0000X | Transplant Nephrology | Nephrologists who manage kidney transplant recipients and order molecular testing |
2080P0207X | Anatomic and Clinical Pathology | Pathologists who oversee biopsy processing and specimen submission |
363LF0000X | Clinical Laboratory | Clinical laboratory directors and technologists responsible for testing logistics and reporting |
207L00000X | Nephrology | General nephrologists involved in post-transplant care and interpretation of results |
Related Diagnoses
| ICD-10 Code | Description | Clinical Relevance |
|---|---|---|
T86.10 | Unspecified complication of kidney transplant | General code for transplant complications prompting molecular evaluation with 0088U |
T86.11 | Kidney transplant failure | Used when graft dysfunction or failure is suspected and molecular testing evaluates risk of progression |
T86.12 | Acute rejection of kidney transplant | Directly relevant when acute rejection is in the differential diagnosis and MMDx helps distinguish rejection type |
N18.6 | End stage renal disease | Historical diagnosis indicating prior kidney failure and transplant status; context for post-transplant surveillance |
N18.9 | Chronic kidney disease, unspecified | Used when chronic dysfunction of a transplanted kidney is being evaluated with molecular testing |
I12.0 | Hypertensive chronic kidney disease with stage 5 CKD or end stage renal disease | Comorbidity that may impact graft function and interpretation of molecular results |
Related CPT Codes
| CPT Code | Description | Relationship to This Procedure |
|---|---|---|
50300 | Kidney biopsy, percutaneous, with imaging guidance when performed | Tissue acquisition procedure that provides biopsy specimen used for the 0088U Molecular Microscope test |
88305 | Level IV surgical pathology, gross and microscopic examination | Routine histopathologic evaluation of the transplant biopsy performed alongside molecular testing |
76942 | Ultrasonic guidance for needle placement (e.g., biopsy) | Imaging guidance commonly used during percutaneous renal transplant biopsy that precedes specimen submission for 0088U |
36415 | Collection of venous blood by venipuncture | May be used for ancillary serologic testing (e.g., donor-specific antibody testing) ordered in the same clinical episode |
86849 | Antibody detection by solid phase (e.g., Luminex) | Donor-specific antibody testing often performed in parallel to molecular diagnostics to assess antibody-mediated rejection |