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.