Coagulation testing can be estimated using two different detection methodologies; one is an optical method and the other a mechanical system.

Coagulation analyzers run the range of options, from automated instruments to manual devices, from high-volume processing to low-volume analysis, and from a wide selection of assays to a small, core group of tests.

Scientists at the Memorial Hospital (Istanbul, Turkey) assayed prothrombin time (PT) and activated partial thromboplastin time (aPTT) on the Coag-a-mate MTX II automated photooptical coagulation analyzer and the AMAX 200 automated photo-mechanical coagulation analyzer. A total of 424 patient samples were included in the study during a period of 15 days and plasma from 25 normal healthy individuals was assayed to obtain the geometric means and reference ranges for PT and aPTT for both the MTX II and AMAX 200 instruments which are marketed by TrinityBioTech (Berkeley Heights, NJ, USA).

The results of the coagulation tests showed good precision ranging between 0.7% and 1.8% coefficient of variation. Statistical analysis demonstrated an excellent correlation between the photooptical and mechanical analyzers for PT and aPTT. Plasma samples from 25 healthy normal donors yielded the following reference ranges: for PT, 10.5-12.3 seconds for MTX II and 11.3-13.4 seconds for the AMAX 200. The ranges for the aPTT were 24.5-33.9 seconds for MTX II and 25.5-35.8 seconds for the AMAX 200.

The authors concluded that all data obtained during the study indicate that the patient results obtained by the photooptical detection system are as reliable and statistically equivalent as those obtained using the mechanical detection system. Most notably, they also found that when testing suboptimal samples, such as those with hyperbilirubinemia or lipemia, the photooptical and mechanical detection methods are statistically equivalent. The study was published in the May 2012 issue of the Journal of Clinical Laboratory Analysis.

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Memorial Hospital
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