Page 21 - qp_17

PROCEDURE FOR EXPERIMENT

1. Measure each specimen pool in triplicates (CLSI requirement)
2. Plot graph the mean of the measured values on the y-axis versus the assign values on

the x-axis ( used XY scatter-excel)
3. Determine the least squares linear regression.

4. Determine slope, intercept, r and within run
5. Acceptable linearity if

a) Slope 1 ± 0.03 or (0.97 to 1.03)

b) Intercept = 0 ± within run (2SD)
c) R > 0.99

Pool Ratio Assigned Replicate
Value
1 2 3 Mean
1 (Low) Neat
2 3:1, Pool 1:5 75/25
3 2:2, Pool 1:5 50/50
4 1:3, Pool 1:5 25/75
5(High) Neat

RESULT ANALYSIS

1. Perform visual review of a plot of the replicate mean of the measured value versus the
true value each level of the sample solutions. Start observation from the highest level.
2. If there is any obvious different between mean of measured value and assigned value,
determine the Systematic Error and Random Error. Then, calculate Total Error.
3. If the total error is smaller than allowable total error (TEa), the reportable range
extended to that particular level.
4. If the total error is larger than TEa, the reportable range should be restricted to a lower
concentration.