Performance characteristics of a new synthetic APTT reagent

Area of Science:

• Clinical Chemistry
• Hematology
• Diagnostic Reagents

Background:

• Activated partial thromboplastin time (APTT) is a critical laboratory test for monitoring anticoagulation and diagnosing coagulation disorders.
• Traditional APTT reagents are often derived from animal sources (e.g., rabbit brain), which can lead to variability and potential supply issues.
• The development of a totally synthetic APTT reagent offers a potential alternative with improved consistency and characteristics.

Purpose of the Study:

• To evaluate the performance characteristics of a new commercially available totally synthetic APTT reagent (Synthasil).
• To compare Synthasil's performance against a conventional rabbit-brain extracted reagent (Thrombosil).
• To assess Synthasil's utility in various clinical scenarios, including heparin therapy, lupus anticoagulants, and factor deficiencies.

Main Methods:

• Comparative analysis of APTT results generated by Synthasil and Thrombosil.
• Testing on normal plasma, heparinized plasma, plasma from patients with lupus anticoagulants, and various factor-deficient plasmas.
• Evaluation of reagent stability under specified storage conditions (24°C for 28 days).

Main Results:

• Synthasil yielded significantly higher normal APTT values compared to Thrombosil.
• APTT ratios were higher with Synthasil in most patients receiving heparin therapy, and Synthasil produced longer APTT values on heparin-spiked normal plasma.
• Synthasil generally produced longer APTTs on lupus anticoagulant and factor-deficient plasmas, though differences were less pronounced or absent when converted to ratios or in specific factor deficiencies (hemophilia A and B).

Conclusions:

• The synthetic APTT reagent Synthasil demonstrates distinct performance characteristics compared to a brain-extracted reagent, notably higher normal values and altered responses in heparinized and certain patient plasmas.
• Synthasil exhibits good stability, with no loss of activity observed after storage at 24°C for 28 days.
• These findings suggest Synthasil may offer a viable alternative, particularly for heparin monitoring, but its interpretation may require adjustments or specific ratio calculations in certain clinical contexts.