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 10 to 20 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 10 to 20 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
(www.idph.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 154.69(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.
