Biomedical Engineering Reference
In-Depth Information
Experiment
. Prepare test whole blood QC pools at medium QC level. Store at
room temperature and 5 °C for 0 (control), 1 and 2 h. Centrifuge the whole
blood sample and collect the plasma (test matrix) for extraction and analysis
following the validation method. Analyze six (6) replicates for each group.
Compare the mean instrument response of stability test samples to that of the
control group.
Acceptance
. The whole stability is acceptable for the period of storage and condi-
tion if the % difference between the stability group and control group is £ 15.0 %
and the RSD for each group is £ 15.0 %.
5.2.12
Evaluation of Hemolysis
Purpose
. To evaluate the presence of hemoglobin in plasma/serum samples for its
effect on the precision and accuracy of the assay being validated.
Experiment
. Prepare hemolyzed plasma or serum by spiking hemolyzed whole
blood into nonhemolyzed plasma at low QC level. Hemolyzed blood for these
experiments can be prepared by freezing, thawing and centrifuging whole blood.
Three levels of hemolysis are used: 0 % (100 % normal plasma/serum), 0.5 %
of above (99.5 % normal plasma/serum), and 2 % of above (98 % normal plasma/
serum). Analyze six (6) replicates for each group. Compare the mean instru-
ment response of the 0.5 % or 2 % hemolysis test samples to that of the 0.0 %
control group.
Acceptance
. Same as described in whole blood stability.
5.3
Cross Validation and Revalidation
5.3.1
Cross Validation
Cross validation is needed on a method that has been received from other institu-
tion or between sites of the same institution. This is to verify ability of the current
laboratory to perform the assay. Most of the time, it requires three precision and
accuracy runs. The evaluations of carryover, recovery, and the ability to dilute may
be excluded if there is reason to believe these parameters will not be affected.
Some or all of the stability evaluations may be excluded if the stability determina-
tions have been adequately evaluated elsewhere and documentation of stability is
available.
5.3.2
Revalidation
Revalidation is required for major changes in assay methods. The extent of the
revalidation depends on those parameters that could be affected by the change that