Experiments in methodological evaluation
Experiments in methodological evaluation
I. Intra-lot reproducibility test
Purpose: To examine the random error of the experimental method and evaluate the precision of the method.
II. Recovery test
Purpose: To detect the proportional systematic error to measure the accuracy of the analytical method .
III. Interference test
Purpose: to examine the constant systematic error of the method to evaluate the accuracy of the candidate method
This experiment is derived from the experiment guide of Mudanjiang Medical College, undergraduate 5-year testing program.
Operation method
Experiments in methodological evaluation Move I. Intra-lot reproducibility test For more product details, please visit Aladdin Scientific website.
1. Repeat the determination of the same sample 20 times within a short period of time in accordance with the prescribed method.
2. Statistical processing: the results of the measurement. Calculate the mean value (X), standard deviation (SD), coefficient of variation (CV) according to the following formula.
X = ∑X/n SD = ∑(X-X)2/n-1 CV = SD/Y × 100%
3. Evaluation: general analysis CV value less than 50%, precision analysis CV value less than 2
Recovery test
1. Sample preparation:
Base sample: serum 2.0ml + distilled water 0.1ml
Low concentration recovery sample: serum 2.0ml + 4mmol/L calcium standard 0.1ml
High concentration recovery sample: serum 2.0m1 + 25mmo1/L calcium standard solution 0.1m1
2. Calculate the added concentration according to the following formula
Addition concentration = standard solution concentration × standard solution volume / serum volume + standard solution volume
3. Measure the concentration in each sample tube more than 3 times.
4. Calculation. Calculate the sample recovery concentration and recovery rate separately
5. Recovered Concentration = Measured Concentration of Recovered Sample - Measured Concentration of Base Sample
Recovery rate = Recovered concentration / added concentration x 100%.
III. Interference test
1. Sample preparation:
Base sample: blood please 1.8m1 + 0.2ml
Low concentration recovery sample: serum 1.8m1 + 63umol/L creatinine standard 0.2ml
High concentration recovery: serum 1.8m1 + 414umol/L creatinine standard 0.2ml
2. Calculate the added concentration according to the following formula
Addition concentration = standard solution concentration × standard solution volume / serum volume + standard solution volume
3. Calculate the concentration in each sample tube
4. Calculate the interference value:
Interference value = measured concentration of interfering sample - measured concentration of interfering sample
5. How to eliminate the interference (discussion)