压电凝血反应频率指数衰减规律及最大曲率终点法的研究

Exponential decay regularity of frequency and endpoint determination by maximal-curvature in piezoelectric coagulation

目的建立压电凝血反应曲线拟合模型及最大曲率终点法判断反应终点。方法用压电石英传感器检测血浆凝血酶原时间,比较指数衰减、幂函数及多项式3种拟合模型的6种曲线的拟合效果,并采用最大曲率终点法判断反应终点。结果6条拟合曲线的非线性回归效果均有显著意义(P<0.05);同类模型内的两条曲线残差平方和(SSE)比较没有显著性差别(P>0.05),而非同类模型之间则差异显著(P<0.01),且多项式SSE最小,指数衰减模型次之,但多项式模型因其曲率存在多个峰值而不能用最大曲率法判断终点;最大曲率终点法比传统的终点频率峰法重复性更好(P<0.05)。结论指数衰减模型Y=A+B×EXP(-X/C)能很好地拟合压电凝血反应曲线;最大曲率终点法能显著提高检测重复性。

Objective To establish a curve fitting model and an endpoint determination by maximal-curvature for the reaction curve of piezoelectric coagulation analysis. Methods A prothrombin time test in plasma was detected by piezoelectric crystal biosensor, fitting effects of six kinds of curves were compared respectively according to three fitting models including exponential decay, power and polynomial category, and the endpoint of the reaction was determined by the maximal curvature. Results Non-linear regression effects of all six curves were perfect （ P 〈 0. 05 ）. The error sum of squares （SSE） among different categories had great deviation significance （P 〈 0. 01 ） while they showed no difference between Polynomial model was the best fitting curve for the piezoelectric two curves in the same category （P 〉0. 10）. coagulation reaction because of its minimal SSE, following by exponential decay. However, the maximal-curvature of polynomial model could not be calculated for its multi-peak values. The precision of maximal-curvature judgment was better than that of the tradi- tional final frequency-peak method （ P 〈 0. 05 ）. Conclusion The exponential decay model [ y = A ＋ B x exp （-x/C） ] can fit the piezoelectric coagulation analysis process perfectly, and it is accessible to calculate the maximal-curvature for endpoint determination to improve the precision of the detection significantly.