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85610
Prothrombin Time (PT)
Code Description
CPT code 85610 is used to report a Prothrombin Time (PT) test, a laboratory study that measures how long it takes blood plasma to clot. The test is commonly used to monitor patients receiving warfarin (Coumadin®) therapy, evaluate bleeding disorders, assess liver function, and help determine clotting abnormalities before surgical procedures. The International Normalized Ratio (INR) is calculated from the PT result and is not reported separately.
When to Use 85610
Common examples include:
Monitoring warfarin therapy
Evaluation of bleeding disorders
Preoperative coagulation testing
Liver disease assessment
Investigation of abnormal bleeding
Monitoring anticoagulant therapy
Evaluation of clotting abnormalities
Documentation Requirements
Documentation should include:
Medical necessity for the laboratory testing
Ordering provider
Laboratory result
Patient diagnosis or symptoms
Date of specimen collection
Complete laboratory report
Examples
Example 1
A patient taking warfarin returns for routine anticoagulation monitoring. The physician orders a Prothrombin Time (PT) test to evaluate clotting time and adjust the medication dosage if needed. CPT code 85610 is reported.
Example 2
A patient scheduled for elective surgery undergoes preoperative laboratory testing. A Prothrombin Time (PT) test is performed to assess blood clotting before the procedure, making CPT code 85610 the appropriate code.
Common Billing Mistakes
Common billing mistakes include:
Reporting 85610 without medical necessity
Billing the INR separately
Duplicate laboratory billing
Insufficient documentation
Incorrect diagnosis coding
Related CPT Codes
85025
Complete Blood Count (CBC) With Automated Differential
85027
Complete Blood Count (CBC)
80053
Comprehensive Metabolic Panel
FAQ
What does CPT code 85610 cover?
CPT code 85610 reports a Prothrombin Time (PT) laboratory test used to evaluate blood clotting and monitor anticoagulant therapy.
What is a Prothrombin Time test used for?
It is commonly used to monitor warfarin therapy, evaluate bleeding disorders, assess liver function, and perform preoperative coagulation testing.
Does CPT 85610 include the INR?
Yes. The INR is a calculated value derived from the PT result and is not separately billable.
When is CPT 85610 commonly performed?
It is frequently performed for patients taking anticoagulants, before surgery, and when evaluating abnormal bleeding or clotting disorders.
Procedure Type
Coagulation Testing
Test Type
Purpose
Prothrombin Time (PT)
Evaluate Blood Clotting
