Aim Hereditary thrombophilic markers are commonly screened among patients diagnosed as having venous thromboembolism, but optimal patient selection and the goals of screening may differ between populations. Determining the patterns of hereditary thrombophilia may improve screening strategies.
Method An unselected cohort of venous thromboembolism patients in three tertiary institutions in Singapore was prospectively tested for the prevalence of deficiencies of protein C, protein S, antithrombin III, factor V Leiden and prothrombin 20210 gene mutations.
Results Among 384 patients screened, the prevalences of protein S, protein C and antithrombin III were 9.20%, 1.18% and 4.19% respectively. Only one patient was positive for the factor V Leiden mutation and none tested positive for the prothrombin 20210 gene mutation. At least 1 in 9 patients (11.52%, 95% CI 8.20 to 15.93) will test positive for one of the above markers in an unselected group of 269 patients who completed all tests. The exclusion of patients with clinical risk factors did not improve the detection rates, in comparison with those with obvious provoking clinical risk factors (11.72%, 95% CI 7.36 to 18.06 vs 11.29%, 95% CI 6.73 to 18.18). When upper age limits were set for thrombophilia screening by decades, a statistical difference in the likelihood of a positive thrombophilia screen between younger and older patient was seen for patients below 40 (p<0.001).
Conclusion In Singapore and countries with similar demographics, hereditary thrombophilia screening should be confined to testing for protein C, protein S and antithrombin III.
- Venous thrombosis
- inherited markers
- risk factors
- vascular disease
- colorectal cancer
- gall bladder
- myeloproliferative disease
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Funding National Medical Research Council, Singapore.
Competing interests None.
Ethics approval Ethics approval was provided by the ethical committee of the participating hospitals' IRB; Singapore General Hospital, National University Hospital and Tan Tock Seng General Hospital.
Provenance and peer review Not commissioned; externally peer reviewed.