Clinical Context
A 68-year-old patient with progressive memory decline is referred by a neurologist for blood-based biomarker testing to assess the likelihood of cerebral amyloid plaque deposition. The clinician documents mild cognitive impairment versus early Alzheimer disease in the history of present illness and orders the proprietary PrecivityAD2™ test to measure plasma beta-amyloid and tau proteins using immunoprecipitation and liquid chromatography–tandem mass spectrometry (LC–MS/MS). A phlebotomy is scheduled at an outpatient laboratory or hospital draw station; the specimen is sent to C2N Diagnostics LLC for analysis. Results provide an algorithm-derived score indicating the probability of amyloid plaque presence, which the ordering clinician integrates with clinical assessment, neuroimaging, and neuropsychological testing to inform diagnostic discussions and care planning.
Coding Specifications
| Modifier | Description | When to Use |
|---|
00 | No modifier; standard reporting | Use when no modifier applies to the laboratory service. |
| 26 | Professional component | Use when reporting only the professional interpretation component if applicable (rare for PLA codes; applies when separate professional interpretation is billed).
| 52 | Reduced services | Use when the test is partially performed or limited in scope compared with the full service.
| 53 | Discontinued procedure | Use when specimen collection or test processing was started but discontinued for patient-related reasons.
| 59 | Data not available in the input. | Data not available in the input.
| 62 | Two surgeons | Use when two qualified independent physicians perform distinct parts of a service; rarely applicable to lab testing workflows.
| 78 | Unplanned return to the operating/procedure room | Use when an unplanned return impacts related services; unlikely for this lab test but retained for clinical relevance.
| 80 | Assistant surgeon | Use when an assistant surgeon is involved; typically not applicable to laboratory testing.
| QK | Medical direction of two, three, or four technicians | Use when the ordering or performing physician provides medical direction over multiple laboratory technicians during complex testing processes.
| QX | Surgical assistant (physical presence) | Use when an assistant meets modifier QX criteria; generally not applicable for PLA reporting.
| Taxonomy Code | Specialty | Notes |
|---|
| 2084P0200X | Neurology | Neurologists commonly order Alzheimer disease biomarker testing to support diagnosis and management. |
| 207RC0000X | Clinical Neurophysiology | Clinicians in neurodiagnostic specialties may be involved in comprehensive cognitive evaluations that include biomarker testing.
| 207L00000X | Clinical Laboratory | Laboratory directors and clinical pathologists oversee specimen processing and analytical quality for specialized PLA tests.
Related Diagnoses
| ICD-10 Code | Description | Clinical Relevance |
|---|
G30.9 | Alzheimer disease, unspecified | Common diagnostic consideration when ordering plasma amyloid/tau testing to assess for amyloid pathology. |
| G31.84 | Mild cognitive impairment, so stated | Typical clinical indication for biomarker testing to help determine etiology and progression risk.
| F02.80 | Dementia in other diseases classified elsewhere without behavioral disturbance | Used when dementia is attributed to another disease; biomarkers help differentiate Alzheimer pathology from other causes.
| R41.3 | Other amnesia | Cognitive symptoms such as amnesia may prompt evaluation including blood-based biomarkers.
| R41.81 | Age-related cognitive decline | Biomarker testing can assist in distinguishing age-related decline from neurodegenerative disease.
Related CPT Codes
| CPT Code | Description | Relationship to This Procedure |
|---|
0503U | PrecivityAD2™; plasma beta-amyloid and tau algorithm score by immunoprecipitation and LC–MS/MS (Proprietary Laboratory Analyses code) | The primary PLA code for the proprietary blood-based Alzheimer disease biomarker test performed by C2N Diagnostics LLC. |
| 80053 | Comprehensive metabolic panel; 14 tests | Often ordered concurrently to assess metabolic contributors to cognitive change and to evaluate general medical status before interpretation of biomarker results.
| 80307 | Drug assay, qualitative; multiple drug classes | May be ordered to exclude substance-related cognitive impairment when clinically indicated prior to biomarker-based diagnostic interpretation.
| 81002 | Urinalysis, non-automated, without microscopy | Ordered as part of routine evaluation to screen for reversible causes of cognitive symptoms.
| 96116 | Neurobehavioral status exam, per hour | Neuropsychological testing commonly complements biomarker testing to document cognitive deficits and support diagnostic conclusions.