New modified activated partial thromboplastin time and prothrombin time methods using a synthetic chromogenic...

Area of Science:

• Biochemistry
• Clinical Chemistry
• Hematology

Background:

• Thrombin plays a critical role in hemostasis.
• Accurate measurement of thrombin activity is essential for diagnosing and monitoring coagulation disorders.
• Existing activated partial thromboplastin time (APTT) and prothrombin time (PT) assays have limitations in sensitivity and specificity.

Purpose of the Study:

• To develop and validate novel modified APTT and PT assays using the chromogenic substrate H-D-Phe-Pip-Arg-pNA (S-2238).
• To assess the performance of these modified assays in detecting thrombin activity.
• To evaluate the correlation between the modified and conventional APTT and PT methods.

Main Methods:

• Utilized S-2238, a specific chromogenic substrate for thrombin, which releases p-nitroaniline (pNA).
• Developed modified APTT and PT methods involving the diazotization of pNA, resulting in a color change from yellow to pink.
• Measured absorbance at 545 nm to quantify thrombin units/ml plasma.

Main Results:

• The modified APTT and PT methods demonstrated significant positive correlations with their respective conventional assays (r = 0.426 for APTT, r = 0.561 for PT; p < 0.01).
• The diazotization reaction enabled sensitive detection of pNA, allowing for accurate thrombin quantification.
• The modified assays provide a reliable alternative for assessing coagulation parameters.

Conclusions:

• The newly developed modified APTT and PT assays using S-2238 and pNA diazotization are effective for measuring thrombin activity.
• These assays offer a valuable tool for clinical diagnostics in coagulation disorders.
• The significant correlations suggest clinical utility and potential for improved diagnostic accuracy.