|2014, Cilt 12, Sayı 2, Sayfa(lar) 079-090
Comparison of the Bhattacharya and Hoffmann Methods as Quality Control Procedures in Indirect Determination of Reference Intervals for Coagulation Tests
Murat Usta1, Hale Aral2, Berrin Berçik İnal2, Güvenç Güvenen3
1Giresun Üniversitesi Tıp Fakültesi, Tıbbi Biyokimya Anabilim Dalı, Giresun
2S.B. İstanbul Eğitim ve Araştırma Hastanesi, Tıbbi Biyokimya Laboratuvarı, İstanbul
3Bezmiâlem Vakıf Üniversitesi Tıp Fakültesi, Tıbbi Biyokimya Anabilim Dalı, İstanbul
Keywords: Coagulation tests; reference ranges; quality control
It's important to determine reliable reference intervals for all the test parameters of the
clinical laboratory, but it's usually hard to obtain useful and necessary clinical data. Although the
procedure of indirect determination of reference intervals using stored data is not defined in any guide,
it was showed that the reference intervals could be estimated by indirect method in lots of studies. We
aimed to constitute a model of using stored data in verifying the reference intervals of prothrombin time
(PT) and activated partial thromboplastin time (APTT) with exclusion of certain clinics in this study.
Materials and Methods: Results of PT (N=11,363) and APTT (N=7,034) test requests of ambulatory
patients aged 15 to 80 made from outpatient clinics of surgical departments before surgical
interventions in 2008 were retrieved from the electronic medical record. Certain clinics were excluded.
Thromborel S and Actin (Dade Behring, Germany) were used for the tests which we done on the Sysmex
CA-1500. We used Bhattacharya and Hoffmann methods as a retrospective quality control procedure for
each study week. When we compared the sensivities of these methods, the results were similar.
Results: We determined the weeks where there was disagreement between the results of internal
quality control and patients' tests and excluded the results of these weeks in estimation. When we
compared the sensivities of these methods (Bhattacharya and Hoffmann), the results were similar.The
indirect reference intervals estimated by using the stored data with the exclusion of certain clinics and
the retrospective evaluation of the internal quality conrol results were overlapping with the data stated
in the insert.
Conclusion: The model which we constituted using stored data, may be particularly suitable for
confirming reference intervals of the laboratory and evaluation of the results of the presenting