Chromogenic assays for equine coagulation factors VII, VIII:C, IX, and X, and C1-esterase inhibitor.

The study aims to convert manual human chromogenic assays, mainly used for testing coagulation factors VII, VIII, IX and X, and C1-esterase inhibitor, to an automated process for horse use. The successful modification of these assays could assist in evaluating haemostasis disorders in horses.

Research Methodology

To establish the compatibility of human chromogenic assays with horses, the researchers used ten healthy horses for the trial and pooled plasma from twenty additional healthy horses for creating standards. The procedure involved the following steps:

• The established manual method for human F.VII, F.VIII:coagulant (F.VIII:C), F.IX (F.IX), F.X (F.X), and C1-esterase inhibitor (C1-INH) chromogenic assay kits was programmed into a computer-assisted analyzer.
• The standards for assays F.VII, F.VIII:C, and F.X were created using pooled citrated equine plasma, whereas commercial pooled citrated human plasma was used for F.IX and C1-INH assays.

Research Findings

The study found that the activity of the proteins under examination in citrated equine plasma from ten horses showed:

• For Factor VII, average activity was 226% with a standard deviation of 19%.
• For Factor VIII:C, the mean activity was approximately 209% with a standard deviation of 31%.
• For Factor IX, the average activity was roughly 149% with a variance of 38%.
• For Factor X, mean activity was about 88% with a standard deviation of 12%.
• For C1-INH, an average activity of 18.4% was observed, with a deviation of 8.4%.

Reliability Testing

The intra-assay coefficients of variation (CV), which measure the accuracy and repeatability of the assays, were:

• 5.3% for F.VII
• 2.1% for F.VIII:C
• 3.0% for C1-INH

The interassay CV, which address the consistency of the assay performance over time, were:

• 5.7% for F.VII
• 7.4% for F.VIII:C
• 3.8% for F.IX
• 14.4% for F.X
• 22.0% for C1-INH

Conclusions

The research concluded that manual human chromogenic assay kits could indeed be automated and used to measure F.VII, F.VIII:C, F.IX, F.X, and C1-INH activities in citrated equine plasma. That implies that these human assays could be used on horses regularly and may significantly improve the evaluation of haemostasis disorders in horses.