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Official Description

Cathepsin-D

© Copyright 2026 American Medical Association. All rights reserved.

Common Language Description

The CPT® Code 82387 refers to the measurement of cathepsin-D levels through a blood test. Cathepsin-D is a specific protein that is encoded by the CTSD gene, which plays a role in various biological processes. This protein belongs to the peptide A1 family and shares structural similarities with pepsin-A, an enzyme involved in the digestion of proteins. The significance of cathepsin-D extends beyond its basic biological function; mutations in the CTSD gene have been associated with serious health conditions, including breast cancer and potentially Alzheimer's disease. As such, measuring cathepsin-D levels can be particularly valuable in clinical settings. It serves as a tumor marker for individuals diagnosed with breast cancer, providing critical information during and after treatment. The test is performed by obtaining a blood sample through a procedure known as venipuncture, which is separately reportable. The serum obtained from the blood sample is then analyzed using a fluorometric assay, a sensitive method that allows for the precise quantification of cathepsin-D levels in the serum.

© Copyright 2026 Coding Ahead. All rights reserved.

1. Indications

The measurement of cathepsin-D levels is indicated for specific clinical scenarios, particularly in the context of oncology and neurodegenerative diseases. The following conditions warrant the performance of this test:

  • Breast Cancer Monitoring The test is utilized as a tumor marker in individuals diagnosed with breast cancer, aiding in the assessment of disease progression and response to treatment.
  • Potential Alzheimer's Disease Association Elevated levels of cathepsin-D may be investigated in relation to Alzheimer's disease, as mutations in the CTSD gene have been linked to this neurodegenerative condition.

2. Procedure

The procedure for measuring cathepsin-D levels involves several key steps that ensure accurate results. First, a qualified healthcare professional performs venipuncture to obtain a blood sample from the patient. This step is crucial as it allows for the collection of serum, which is the component of blood that will be tested. The venipuncture site is typically cleaned with an antiseptic to minimize the risk of infection. Once the blood is drawn, it is collected in a sterile container and processed to separate the serum from the cellular components of the blood. Following the collection, the serum is subjected to a fluorometric assay. This assay is a sophisticated testing method that utilizes fluorescence to measure the concentration of cathepsin-D in the serum. The fluorometric assay is known for its sensitivity and specificity, making it an effective choice for quantifying protein levels in biological samples.

3. Post-Procedure

After the blood sample has been collected and the serum tested, there are generally no specific post-procedure care requirements for the patient. However, it is important for healthcare providers to monitor the patient for any immediate reactions to the venipuncture, such as bruising or discomfort at the site. The results of the cathepsin-D test will be analyzed and reported, providing valuable information for the ongoing management of patients with breast cancer or those being evaluated for Alzheimer's disease. Follow-up consultations may be necessary to discuss the results and any further diagnostic or therapeutic steps that may be indicated based on the findings.

Short Descr ASSAY OF CATHEPSIN-D
Medium Descr CATHEPSIN-D
Long Descr Cathepsin-D
Status Code Statutory Exclusion (from MPFS, may be paid under other methodologies)
Global Days XXX - Global Concept Does Not Apply
PC/TC Indicator (26, TC) 9 - Not Applicable
Multiple Procedures (51) 9 - Concept does not apply.
Bilateral Surgery (50) 9 - Concept does not apply.
Physician Supervisions 09 - Concept does not apply.
Assistant Surgeon (80, 82) 9 - Concept does not apply.
Co-Surgeons (62) 9 - Concept does not apply.
Team Surgery (66) 9 - Concept does not apply.
Diagnostic Imaging Family 99 - Concept Does Not Apply
CLIA Waived (QW) No
APC Status Indicator Conditionally packaged laboratory tests
Type of Service (TOS) 5 - Diagnostic Laboratory
Berenson-Eggers TOS (BETOS) T1H - Lab tests - other (non-Medicare fee schedule)
MUE 1
CCS Clinical Classification 233 - Laboratory - Chemistry and Hematology
XU Unusual non-overlapping service, the use of a service that is distinct because it does not overlap usual components of the main service
26 Professional component: certain procedures are a combination of a physician or other qualified health care professional component and a technical component. when the physician or other qualified health care professional component is reported separately, the service may be identified by adding modifier 26 to the usual procedure number.
90 Reference (outside) laboratory: when laboratory procedures are performed by a party other than the treating or reporting physician or other qualified health care professional, the procedure may be identified by adding modifier 90 to the usual procedure number.
GW Service not related to the hospice patient's terminal condition
Date
Action
Notes
1993-01-01 Added First appearance in code book in 1993.
Code
Description
Code
Description
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