What diagnosis codes cover a full thrombotic (blood clot) workup?

Diagnosis Codes for Full Thrombotic Workup

For a full thrombotic (blood clot) workup, the most appropriate ICD-10 codes should be selected based on the suspected condition, symptoms, or family history that necessitates the testing. 1

Primary Diagnosis Codes

Suspected Thrombotic Disorders:

• D68.5 - Primary thrombophilia
• D68.61 - Antiphospholipid syndrome
• D68.62 - Lupus anticoagulant syndrome
• D68.69 - Other thrombophilia
• I82.0-I82.9 - Other venous embolism and thrombosis (specific to site)

For Evaluation of Symptoms:

• R07.1 - Chest pain on breathing (if PE suspected)
• R60.0 - Localized edema (if DVT suspected)
• I97.8 - Other intraoperative and postprocedural complications of circulatory system

For Family History:

• Z82.49 - Family history of ischemic heart disease and other diseases of the circulatory system
• Z86.718 - Personal history of venous thrombosis and embolism

Testing Components Based on Guidelines

A full thrombotic workup typically includes the following components, each requiring appropriate diagnostic coding 1, 2:

1. Initial Assessment:

   • Complete blood count (CBC) with platelet count
   • Prothrombin time (PT)
   • Activated partial thromboplastin time (aPTT)
   • Fibrinogen levels

2. Specialized Testing:

   • D-dimer testing
   • Imaging studies (ultrasound, CT venography, MR venography)
   • ADAMTS13 activity (for TTP evaluation)
   • Von Willebrand factor assays (VWF antigen, VWF ristocetin cofactor activity)
   • Factor VIII coagulant activity

3. Thrombophilia Testing:

   • Protein C and S activity
   • Antithrombin III activity
   • Factor V Leiden mutation
   • Prothrombin G20210A mutation
   • Lupus anticoagulant
   • Anticardiolipin antibodies
   • Beta-2 glycoprotein antibodies

Coding Strategy

For Initial Presentation:

1. Code the suspected condition first (e.g., I82.409 for acute embolism and thrombosis of unspecified deep veins of unspecified lower extremity)
2. Add symptom codes that support medical necessity
3. Include any relevant risk factor codes (e.g., obesity, malignancy, pregnancy)

For Follow-up Testing:

1. Use Z codes for follow-up or screening based on personal or family history
2. Include any abnormal findings from previous tests

Important Considerations

• Medicare and many commercial payers require specific ICD-10 codes to justify thrombophilia testing 1
• Testing for inherited platelet function disorders requires careful clinical evaluation including personal and family bleeding history 1
• The International Society on Thrombosis and Haemostasis (ISTH) recommends using bleeding assessment tools to identify patients needing further investigations 1
• For suspected upper extremity DVT, combined-modality ultrasound is recommended as the initial evaluation 1

Common Coding Pitfalls

• Using only symptom codes without suspected condition codes
• Failing to document family history when it's the primary reason for testing
• Using unspecified codes when more specific codes are available
• Not updating diagnosis codes when test results confirm or rule out specific conditions

Remember that medical necessity must be clearly documented in the medical record to support the diagnostic codes used for thrombotic workup, and the codes should reflect the highest level of specificity based on the available clinical information 1, 2.