A comparison of five manually operated coagulation instruments

Area of Science:

• Clinical Chemistry
• Hematology
• Medical Diagnostics

Background:

• Accurate coagulation testing is crucial for patient management.
• Several automated instruments are available for prothrombin time (PT) and activated partial thromboplastin time (APTT) analysis.
• Evaluating instrument performance is essential for reliable laboratory results.

Purpose of the Study:

• To compare the precision, reproducibility, and accuracy of five different coagulation instruments.
• To assess the performance of single-channel analyzers against a reference instrument.
• To identify instruments suitable for routine clinical use.

Main Methods:

• Comparative analysis of PT and APTT results from Coag-a-Mate, Coagulyzer Jr., Clotek, Electra 650, and Fibrometer.
• Evaluation of precision using coefficient of variation (CV).
• Assessment of day-to-day reproducibility and correlation with a reference instrument (Bio/Data CA-15).

Main Results:

• No significant differences were observed among instruments for PT analysis.
• The single-channel Coag-a-Mate demonstrated the best APTT precision (CV 2-4%).
• Coag-a-Mate and Electra 650 exhibited the best APTT day-to-day reproducibility (CV 2-5%).
• Good correlation (r ≥ 0.95) was found between the reference instrument and Coag-a-Mate, Electra 650, and Clotek.
• Coagulyzer Jr. showed good correlation (r = 0.95) but missed some clots. Fibrometer had poorer correlation (r = 0.87).

Conclusions:

• Coag-a-Mate and Electra 650 are reliable instruments for APTT testing, offering good precision and reproducibility.
• Most evaluated instruments, except Fibrometer, provide acceptable PT and APTT results.
• Instrument selection should consider specific performance characteristics, including clot detection capabilities.