Current through Register Vol. 47, No. 6, September 18, 2024
The laboratory shall have quality control protocols that
include the following elements:
(1)
Quality control samples required.
a. The laboratory shall run quality control
samples with every analytical batch of samples for chemical and microbiological
analysis.
b. For microbiological
analysis, the laboratory shall develop procedures for quality control
requirements for each analytical batch of samples.
c. The laboratory shall analyze the quality
control samples in exactly the same manner as the test samples to validate the
laboratory testing results.
(2)
Types of quality control
samples. At a minimum, a laboratory shall have the following quality
control samples as part of every analytical batch tested for chemical analytes:
a. Negative control (method blank). A
laboratory shall prepare and run at least one method blank sample with an
analytical batch of samples along with and under the same conditions, including
all sample preparation steps, as the other samples in the analytical batch, to
demonstrate that the analytical process did not introduce
contamination.
b. Positive control
(laboratory control sample). A laboratory shall prepare and run at least one
laboratory control sample with an analytical batch of samples along with and
under the same conditions, including all sample preparation steps, as the other
samples in the analytical batch.
c.
Matrix spike sample. A laboratory shall prepare and run one or more matrix
spike samples for each analytical batch.
(1) A
laboratory shall calculate the percent recovery for quantitative chemical
analysis by dividing the sample result by the expected result and multiplying
that by 100. All quality control measures shall be assessed and evaluated on an
ongoing basis, and quality control acceptance criteria shall be used. When
necessary, the department may establish acceptance criteria on the department's
website (hhs.iowa.gov).
(2) If
quality control acceptance criteria are not acceptable, a laboratory shall
investigate the cause, correct the problem, and rerun the analytical batch of
samples. If the problem persists, the laboratory shall reprepare the samples
and run the analysis again, if possible.
d. Field duplicate sample. A laboratory shall
prepare and run a duplicate sample as described in the laboratory testing
requirements and acceptance criteria document in subrule 154.47(1). The
acceptance criterion between the primary sample and the duplicate sample is
less than or equal to 20 percent relative percent difference.
(3)
Certified reference
material for chemical analysis. The laboratory shall use a reference
material for each analytical batch in accordance with the following standards:
a. The reference material should be certified
and obtained from an outside source, if possible. If a reference material is
not available from an outside source, the laboratory shall make its own
in-house reference material.
b.
Reference material made in-house should be made from a different source of
standards than the source from which the calibration standards are
made.
c. The test result for the
reference material shall fall within the quality control acceptance criteria.
If it does not, the laboratory shall document and correct the problem and run
the analytical batch again.
(4)
Calibration standards.
The laboratory shall prepare calibration standards by serially diluting a
standard solution to produce working standards used for calibration of an
instrument and quantitation of analyses in samples.
(5)
Quality control-sample
report. A laboratory shall generate a quality control-sample report
that includes quality control parameters and measurements, analysis date, and
type of matrix.
(6)
Limit-of-detection and limit-of-quantitation calculations. For
chemical method analysis, a laboratory shall calculate the limit of detection
and limit of quantitation using generally accepted methodology.
