170 T . Matsumoto et al .: J Extra Corpor Technol 2023 , 55 , 167 – 174
was set at 3 min after switching the test circuit to measurement status .
Statistical analysis
Among continuous variables , absolute values are expressed as mean ± standard deviation ( SD ). The Pearson productmoment correlation coefficient was calculated to determine correlations between measurement methods . JMP software ( version 14.3.0 ; SAS Institute , Tokyo , Japan ) was used for statistical analysis , and a p-value of < 0.05 was considered statistically significant .
Results Experiment 1
Figure 3 . Sequence of events during testing .
solution ( FUJIFILM Wako Pure Chemical Corporation , Osaka , Japan ).
For each test liquid , COP was measured 10 times with the test method and samples for comparison . For each COP measurement , the process was repeated from the pre-measurement preparation state , blood was circulated for 5 min , the standby time began , and the next measurement was performed . After the COP measurement of test liquid 8 , test liquid 9 was prepared , and its COP measurement was performed . Similarly , experiments were sequentially conducted to test liquid 10 . Therefore , all test liquids were prepared within the circuit . During the preparation of test liquids , ultrafiltration was performed for over 30 minutes and the blood flow rate was varied . The blood flow rates during the preparation of the test liquids were 200 mL / min for test liquid 8 , 300 mL / min for test liquid 9 , and 400 mL / min for test liquid 10 .
Parameters for evaluation Simultaneous reproducibility
The coefficient of variation ( CV ) was calculated from the COP values obtained from measuring each test solution 10 times .
Correlation
Measurements were plotted on the x- and y-axes and the Pearson product-moment correlation coefficient was calculated .
Measurement time
The time required for measurement was determined as the time required for the completion of solvent migration during the standby time . The standby time was defined as the time required for the completion of solvent migration through osmolality difference and for equilibration ; the standby time
The Hct concentrations measured with test liquids 1 – 7 were listed in Table 2 .
Simultaneous reproducibility
The CV was within 3 % for all 10 measurements of each test liquid . For Experiment 1 , the test method was 1.44 ± 0.66 % and the colloid osmometer was 0.99 ± 0.34 %. Satisfactory results of under 3 % were obtained for all cases ( Table 2 ).
Correlation
COP as measured by the test method and the colloid osmometer demonstrated a strong correlation ( Pearson product-moment correlation coefficient R 2 = 0.998 , p < 0.01 ). The formula for the regression line is as follows ( Figure 4 ):
y ¼�0:815074 þ 1:1085785 x : ð1Þ
Measurement of time
Although the standby time was 3 min , solvent transfer of test liquid 1 was completed in approximately 10 seconds . Solvent transfer time grew longer as the concentration of the test liquid increased . Solvent transfer for test liquid 7 took approximately 1 min to complete . In all cases , no solvent transfer was observed after 2 min of the 3-min standby time had elapsed .
Experiment 2
The Hct concentrations measured with test liquids 8 – 10 were listed in Table 3 . The COP of the aqueous albumin solution was 26.8 mmHg using the colloid osmometer .
Simultaneous reproducibility
The CV was within 3 % for all 10 measurements of each concentration . Overall , for Experiment 2 , the test method was 1.67 ± 0.51 % and the colloid osmometer was 0.90 ± 0.04 %. Satisfactory results of under 3 % were obtained in all cases ( Table 3 ).