title: Inappropriate use of protein C, protein S, and antithrombin testing for hereditary thrombophilia screening: an experience from a large university hospital.
abstract: BACKGROUND
  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.
  
  
  CONCLUSIONS
  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.
authors.affiliation: Department of Clinical Pathology, Faculty of Medicine, Siriraj Hospital, Mahidol University, Bangkok, Thailand. siptd@mahidol.ac.th
authors.forename: P
authors.initials: P
authors.lastname: Tientadakul
authors.forename: Y
authors.initials: Y
authors.lastname: Chinthammitr
authors.forename: K
authors.initials: K
authors.lastname: Sanpakit
authors.forename: C
authors.initials: C
authors.lastname: Wongwanit
authors.forename: Y
authors.initials: Y
authors.lastname: Nilanont
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000990:Antithrombin III / Q000032:analysis*; D044466:Asian People; D002648:Child; D002675:Child, Preschool; D004797:Enzyme-Linked Immunosorbent Assay; D006785:Hospitals, University; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D008403:Mass Screening / Q000379:methods* / Q000592:standards; D008875:Middle Aged; D011486:Protein C / Q000032:analysis*; D017293:Protein S / Q000032:analysis*; D015203:Reproducibility of Results; D012189:Retrospective Studies; D013785:Thailand; D019851:Thrombophilia / Q000097:blood / Q000175:diagnosis* / Q000208:ethnology; D055815:Young Adult
chemical_list: D011486:Protein C; D017293:Protein S; D000990:Antithrombin III