Single or duplicate analysis for automated prothrombin time and activated partial thromboplastin time?

Area of Science:

• Clinical Pathology
• Laboratory Medicine
• Hematology

Background:

• Automated coagulation analyzers enable single routine coagulation tests instead of duplicates.
• Prothrombin time (PT) and activated partial thromboplastin time (aPTT) are common coagulation assays.

Purpose of the Study:

• To compare duplicate and single test results for PT and aPTT.
• To evaluate the clinical significance and interchangeability of single coagulation tests.
• To assess the feasibility of implementing single testing in a laboratory setting.

Main Methods:

• Compared duplicate PT and aPTT results with single results from an MLA Electra 1000c analyzer.
• Method 1: Assessed clinical significance by comparing mean duplicate and single results.
• Method 2: Statistically evaluated agreement between mean duplicate and single results using 95% confidence intervals.

Main Results:

• Clinically significant differences were rare: 0.048% for PT and 0.065% for aPTT.
• Statistical analysis confirmed interchangeability of single and duplicate results for clinical interpretation.
• The study supported the adoption of single testing for PT and aPTT.

Conclusions:

• Single testing for PT and aPTT is a viable and clinically acceptable alternative to duplicate testing.
• Implementation requires updated quality control, machine maintenance, and repeat testing protocols.
• This shift optimizes laboratory efficiency without compromising patient management.