Coding Ahead
CasePilot
Medical Coding Assistant
Case2Code
Search and Code Lookup Tool
RedactPHI
HIPAA-Compliant PHI Redaction
DetectICD10CM
ICD-10-CM Code Detection
Log in Register free account
1 code page views remaining. Guest accounts are limited to 1 page view. Register free account to get 5 more views.
Log in Register free account
CPT®
85335

CPT® Code 85335

Official Description

Factor inhibitor test

© Copyright 2025 American Medical Association. All rights reserved.

Common Language Description

The CPT® Code 85335 refers to a laboratory test known as the factor inhibitor test. This test is specifically designed to measure the activity of factor inhibitors, which are IgG antibodies that can develop against clotting factors in the blood. The presence of these inhibitors can significantly impact the effectiveness of clotting factor concentrates, leading to complications such as treatment failure, bleeding episodes, and potentially life-threatening hemorrhages. Factor inhibitors are most commonly observed in patients suffering from hemophilia A, which is associated with a deficiency in factor VIII, and hemophilia B, linked to a deficiency in factor IX. These patients often receive clotting factor concentrates as part of their treatment regimen for their hemolytic disorders. However, it is important to note that inhibitor factor antibodies can also arise in other populations, including elderly individuals without a prior history of hemophilia, postpartum women, and patients with various autoimmune disorders. The test itself involves obtaining a blood sample through a venipuncture, which is reported separately, and the analysis is conducted on platelet-poor plasma using a clot-based assay to accurately assess the inhibitor activity.

© Copyright 2025 Coding Ahead. All rights reserved.

1. Indications

The factor inhibitor test (CPT® Code 85335) is indicated for several specific conditions and patient populations where the presence of factor inhibitors may complicate treatment and management. The following are the primary indications for performing this test:

  • Hemophilia A Patients with a deficiency in factor VIII who are receiving clotting factor concentrates may develop factor inhibitors, necessitating this test to monitor their treatment efficacy.
  • Hemophilia B Individuals with a deficiency in factor IX are also at risk for developing factor inhibitors, making this test crucial for assessing their response to treatment.
  • Postpartum Women Women who have recently given birth may develop factor inhibitors, and testing can help identify any complications related to clotting factors.
  • Elderly Patients Older adults without a history of hemophilia may also develop factor inhibitors, warranting testing to ensure proper management of their coagulation status.
  • Patients with Autoimmune Disorders Individuals with certain autoimmune conditions may be at risk for developing factor inhibitors, making this test relevant for their care.

2. Procedure

The procedure for conducting the factor inhibitor test involves several key steps to ensure accurate measurement of factor inhibitor activity. The following outlines the procedural steps:

  • Step 1: Patient Preparation Prior to the test, the patient may be instructed to avoid certain medications or activities that could affect the results. It is essential to gather a thorough medical history to identify any potential risk factors for the development of factor inhibitors.
  • Step 2: Venipuncture A blood sample is obtained through a venipuncture, which is a procedure where a needle is inserted into a vein to collect blood. This step is crucial as the sample must be collected in a manner that minimizes contamination and ensures the integrity of the specimen.
  • Step 3: Plasma Preparation After collection, the blood sample is processed to separate the plasma. Specifically, platelet-poor plasma is prepared, which is essential for the subsequent testing phase to accurately measure factor inhibitor activity.
  • Step 4: Clot-Based Assay The prepared platelet-poor plasma is then subjected to a clot-based assay. This assay is designed to detect the presence and activity of factor inhibitors by observing the clotting process in the presence of specific clotting factors.
  • Step 5: Result Interpretation Once the assay is complete, the results are analyzed and interpreted by a qualified laboratory professional. The findings will indicate whether factor inhibitors are present and their level of activity, which is critical for guiding treatment decisions.

3. Post-Procedure

After the factor inhibitor test is completed, there are several considerations for post-procedure care. Patients may experience minor discomfort at the venipuncture site, which typically resolves quickly. It is advisable for patients to monitor the site for any signs of excessive bleeding or infection. The results of the test will be communicated to the healthcare provider, who will interpret the findings in the context of the patient's overall clinical picture. Depending on the results, further testing or adjustments to the treatment plan may be necessary to address any identified factor inhibitors. Continuous monitoring may be required for patients with known hemophilia or those at risk for developing inhibitors, ensuring that their treatment remains effective and safe.
Short Descr FACTOR INHIBITOR TEST
Medium Descr FACTOR INHIBITOR TEST
Long Descr Factor inhibitor test
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 2
CCS Clinical Classification 233 - Laboratory - Chemistry and Hematology
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.
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.
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
CasePilot

Get instant expert-level medical coding assistance.

Ask about:
CPT Codes Guidelines Modifiers Crosswalks NCCI Edits Compliance Medicare Coverage
Example: "What is CPT code 99213?" or "Guidelines for E/M services"