Research of applicability of control samples in measurement of whole blood viscosity / 中华检验医学杂志

ABSTRACT

Objective To exlore the influence of internal quality control and external quality control assessment(EQA) resulting from applicability of control samples in measurement of whole blood viscosity (WBV) through the analysis and comparison of applicability of 1 non-Newtonian fluid internal quality control sample in 3 viscometers. Methods Viscometer B, C and D were used to measure WBV of 30 blood samples in parallel under the shear rate(SR) of 1 s-1,30 s~(-1) and 200 s~(-1), then the blood SR-WBV curves of 3 viscometers were drawn according to the results. At the same time, viscometers B, C and D were used respectively to determine the WBV of control A 10 times in one day, then the control A SR-WBV curves were mapped. Three viscometers were used to measure the manufactory control samples and control A 5 times in one day for 4 days. Four groups of daily values of manufactory control samples and control A of each instrument were used to carry out F test to calculate whether 4 daily values are difference. Finally, the control A was dispensed in 49 laboratories nationwide chosen for measurement. On the basis of viscometer used, 20 laboratories were classified as group B, 20 laboratories were classified as group C and 9 laboratories were classified as group D. Then the data under SR of 1 s~(-1) were analyzed to calculate the coefficient of variation (CV) in the group. Results There was significant difference among the WBV of blood samples measured by the viscometers B, C and D. The results under SR of 1 s~(-1) declined in turn, and they were highest under SR of 30 s~(-1) followed by the values of viscometer D and B and they were (8.14±0.75), highest under SR of 30 s-1 followed by the values of viscometer B and D, and they were (7.35±0.07), daily values of manufactory control and control A of each instruments in four groups were compared. Under SR of 1 s~(-1), there was no difference between daily values of manufactory control and control A in viscometer B (F = 2.63, 1.37, P > 0.05), and there was no difference of daily values of manufactory control among viscometer C and D (F = 0.33,3. 14, P > 0.05), but significant daily difference existed when control A was tested by viscometer C and D (F = 5.76, 8.00, P < 0.05). Under SR of 30 s~(-1), there was no difference of daily values of manufactory control among 3 viscometers(F =0.31, 0.18, 2.26, P >0.05), and there was no difference of daily values of control A among 3 viscometers' (F = 1.03, 1.83, 2.40, P > 0.05); Under SR of 200 s~(-1), there was no difference of daily values of manufactory control among 3 viscometers (F =2.59, 0.68, 2.96, P > 0.05), and there was no difference of daily values of control A among 3 viscometers (F=2.31, 3.01, 2.28, P>0.05). When control A was tested under SR of 1 s~(-1) in 49 laboratories nationwide, the WBV values in groups of viscometer B, C and D were (18.47±1.30), (11.17±2.38), viscometer D and C were 63.75% and 21.3%. Conclusions Control A could fully mimic the properties of whole blood steadily on viscometer B, but partially mimic viscometer C and D, so the control A is most appropriate for viscometer B. Because current non-Newtonian fluid internal quality control could mimic rheological properties of whole blood under specifically conditions, laboratories should evaluate the consistent degree between control and whole blood, only the candidates which can mimic the properties of whole blood approximately could be chosen as quality control of WBV. When third-party control is chosen to be samples of EQA, its applicability should be in consideration. Pretest should be performed adequately to define applicability of third-party control, so as to reduce the difference among laboratories due to applicability of control and reflect detection quality of laboratories exactly.