Summary & Overview
CPT 0512U: Tempus p–MSI Digital MSI Probability Test for Prostate Cancer
CPT code 0512U designates Tempus p–MSI, a Proprietary Laboratory Analyses (PLA) test that uses algorithmic analysis of digitized whole–slide imaging to estimate the probability of microsatellite instability–high (MSI–H) in prostate cancer tissue. MSI–H status can have therapeutic implications, as tumors with MSI–H may be candidates for immunotherapy. Nationally, PLA codes like 0512U are significant because they identify single-manufacturer tests with unique clinical workflows and payer considerations.
Key payers commonly reviewed for coverage and reimbursement include Aetna, Blue Cross Blue Shield, Cigna Health, UnitedHealthcare, and Medicare. Readers will find a concise overview of the clinical context for MSI testing in prostate cancer, the service model and typical site of service for this digital pathology assay, and the payer landscape relevant to single-source laboratory diagnostics. The publication summarizes benchmark considerations for PLA-coded services, outlines common billing modifiers used with laboratory and pathology services, and highlights policy and coding factors that affect national access to proprietary digital pathology assays.
This summary is intended to inform clinicians, laboratory managers, and policy analysts about the clinical purpose of CPT code 0512U, the service setting, and the payer environment relevant to a unique digital image–based MSI classifier.
Billing Code Overview
CPT code 0512U is a Proprietary Laboratory Analyses (PLA) code reported only for Tempus p–MSI developed by Tempus AI Inc. The test applies algorithmic analysis of digitized whole–slide imaging to estimate the probability that prostate cancer tissue is microsatellite instability–high (MSI–H). MSI–H status may identify tumors that are candidates for immunotherapy.
Service type: Laboratory pathology service — digital image analysis for tumor biomarker classification
Typical site of service: Clinical laboratory or pathology service processing digitized whole–slide images; specimen origin is prostate cancer tissue submitted by outpatient or inpatient pathology services
Clinical & Coding Specifications
Clinical Context
A 68-year-old man with a history of rising prostate-specific antigen (PSA) and a prior prostate needle biopsy demonstrating adenocarcinoma undergoes radical prostatectomy. The surgical pathology specimen shows features concerning for mismatch repair deficiency. The treating oncologist orders the Tempus p–MSI test (0512U) to evaluate the probability that the prostate tumor is microsatellite instability–high (MSI–H) using algorithmic analysis of digitized whole–slide images. The laboratory receives the formalin-fixed, paraffin-embedded tissue slide images or whole-slide scans and performs the proprietary digital image analysis. Results reporting provides a probability score for MSI–H which the oncology team uses to consider eligibility for immune checkpoint inhibitor therapy and to inform genomic workup decisions.
Typical workflow:
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Tissue specimen processed by the surgical pathology laboratory and slides scanned to whole-slide images.
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Pathologist reviews slides and documents tumor area; digital images and clinical requisition are sent to Tempus AI Inc. or performed within the proprietary Tempus environment.
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Tempus p–MSI analysis (
0512U) is performed, generating an MSI probability result and technical report. -
Result is transmitted to the ordering oncologist and integrated into the electronic medical record for treatment planning and potential referral to medical oncology for immunotherapy evaluation.
Coding Specifications
| Modifier | Description | When to Use |
|---|---|---|
26 | Professional component | When billing only the professional interpretation component separate from the technical component |
TC | Technical component | When billing only the technical component (image generation/processing) separate from interpretation |
QK | Medical direction of two to four eligible professionals | When the physician directs 2–4 qualified individuals in performance of the test procedures (rare for PLA but applicable if applicable staffing applies) |
QX | Modifier certifying CLIA compliance for assistant personnel | When CLIA-qualified personnel performed part of the test under physician/purchasing lab supervision as applicable |
QY | Attending absence; patient not present (clinical lab specific) | When specific laboratory regulatory modifiers apply for split billing scenarios |
52 | Reduced services | When the specimen or analysis is partially completed or fewer images were available resulting in reduced service |
53 | Discontinued procedure | When the test was started but discontinued due to specimen inadequacy or other valid reason |
80 | Assistant surgeon | When an assistant surgeon is billed for related surgical specimen procurement (used on surgical billing, not on PLA code itself) |
62 | Two surgeons | When two surgeons performed the operative procedure that generated the tissue specimen (surgical billing context) |
22 | Unusual procedural services | When the service required substantially greater effort or time beyond typical complexity |
| Taxonomy Code | Specialty | Notes |
|---|---|---|
| 207RH0000X | Anatomic Pathology | Pathologists oversee slide preparation, review, and selection for digital analysis |
| 208000000X | General Oncology | Medical oncologists order MSI testing for treatment planning and immunotherapy eligibility |
| 207L00000X | Surgical Pathology | Surgical pathologists commonly handle diagnostic interpretation and specimen selection |
| 208000000X | Urology | Urologists obtain tissue via biopsy or prostatectomy and coordinate diagnostic workup |
| 207K00000X | Diagnostic Radiology | Radiologists performing image-guided biopsies that yield the tissue specimens |
Related Diagnoses
| ICD-10 Code | Description | Clinical Relevance |
|---|---|---|
C61 | Malignant neoplasm of prostate | Primary diagnosis for prostate cancer tissue submitted for MSI assessment |
D07.5 | Carcinoma in situ of prostate | Rarely used but may prompt molecular assessment if invasive components suspected |
N41.9 | Inflammatory disease of prostate, unspecified | Inflammatory changes can confound histologic interpretation and may trigger additional testing |
R97.2 | Elevated prostate specific antigen [PSA] | Elevated PSA often leads to biopsy and subsequent tumor tissue analysis including MSI testing |
Z85.46 | Personal history of malignant neoplasm of prostate | Follow-up or recurrence evaluation where MSI status may guide therapy |
Related CPT Codes
| CPT Code | Description | Relationship to This Procedure |
|---|---|---|
88342 | Immunohistochemistry or special stains, per single antibody stain; interpretation and report | Performed on tissue to identify protein expression that may correlate with MSI/MMR status prior to or alongside digital MSI analysis |
88360 | Computer-assisted morphometric analysis | May be reported when pathology uses computer-assisted image analysis for morphometry; related to whole-slide image analysis workflows |
88305 | Level IV surgical pathology, gross and microscopic examination | Typical pathology accessioning and diagnostic interpretation code for prostatectomy or biopsy specimens that generate slides used by the PLA |
88313 | Immunohistochemistry, each additional stain (list separately in addition to primary) | Additional IHC stains for mismatch repair proteins (MLH1, MSH2, MSH6, PMS2) often performed in parallel with MSI assessment |
81275 | Mismatch repair (MMR) gene testing; MSH6 (eg, sequencing) | Molecular testing of MMR genes may be ordered following MSI probability results to confirm underlying genetic alterations |