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Inappropriate use of protein C, protein S, and antithrombin testing for hereditary thrombophilia screening: an
P Tientadakul1, Y Chinthammitr, K Sanpakit
1Department of Clinical Pathology, Faculty of Medicine, Siriraj Hospital, Mahidol University, Bangkok, Thailand. siptd@mahidol.ac.th
Insights
Testing for inherited thrombophilia in Thai patients is often inappropriate, particularly during acute thrombosis. Physician education on proper patient selection and test timing is crucial for improving screening test utilization.
Area of Science:
- Hematology
- Clinical Pathology
Background:
- Inherited deficiencies of protein C, protein S, and antithrombin are key inherited risk factors for venous thromboembolism in Thai patients.
- However, the prevalence of these deficiencies is not high in this population.
Purpose of the Study:
- To evaluate the appropriateness of hereditary thrombophilia screening test orders in Thai patients.
- To assess the reliability of test order reviews.
Main Methods:
- Retrospective review of 503 patient test orders against proposed guidelines.
- Calculation of inter-rater reliability between two investigators.
Main Results:
- A high rate of inappropriateness (91%) was observed in test orders.
- The primary reason for inappropriate testing was performance during acute thrombosis (42.5%).
- Inconclusive results were frequent (20.9%), often due to lack of confirmatory testing for decreased protein levels. Inter-rater reliability was good (Kappa index = 0.79).
Conclusions:
- Physician education is essential to improve the appropriate use of hereditary thrombophilia screening tests.
- Emphasis should be placed on correct patient selection, optimal timing for testing, and the necessity of repeating abnormal results.
Introduction:
Deficiencies of protein C, protein S, and antithrombin are the main inherited risk factors in Thai patients with venous thromboembolism, although the prevalence is not high.
Methods:
To evaluate the appropriate use of the testing for these proteins, the test orders of 503 patients were retrospectively reviewed using the proposed guidelines. Inter-rater reliability between two investigators was also calculated.
Results:
Of 503, 459 (91%; 95% confidence interval 88-93%) of the test orders were inappropriate. The most common cause of inappropriateness was testing during acute thrombosis (42.5%). Results were inconclusive in 105 (20.9%) patients who had isolated decrease in one of the proteins, mostly owing to lack of confirmation of the abnormal results. Kappa index for the reliability of two investigators was 0.79.
Conclusion:
To enhance the appropriate use of hereditary thrombophilia screening tests, physician education concerning the patient selection, suitable timing for testing and repetition of the tests with abnormal results should be emphasized.
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