Washington Administrative Code › Title 16 - Agriculture, Department of (See also Titles 24, 60, and 142) › SEEDS AND PLANTING STOCK CERTIFICATION › Chapter 16-309 - Cannabis laboratory accreditation standards program › Section 16-309-260 - Method validations

Current through Register Vol. 24-14, July 15, 2024
(1) Laboratories
				must perform method validation studies prior to implementing a new or original
				test method, implementing an approved method, implementing a new instrument, or
				modifying an existing method or instrument for each matrices tested.
(2) The records must include sufficient
				information to allow for a comprehensive review of the studies performed.
				Laboratories must have criteria for acceptance of study data, for agreement of
				replicate study samples, and for defining true outlier values. Study samples
				for quantitative methods must meet the same qualitative criteria (e.g., the
				same retention time, mass ratio, internal standard abundance, and
				chromatography criteria) used for samples. The laboratory's acceptance criteria
				must be described in the SOP and in the study summary.
(3) Laboratories must perform reverification
				studies on an annual basis at minimum on high complexity nonreagent methods.
				Reverification studies are designed to verify that the existing LOD, LOQ, and
				ULOL values are still valid and do not require laboratories to analyze the same
				number of samples that are required for full validation studies.
(4) If the laboratory modifies an existing
				test method or instrument parameter that affects the performance of the method,
				the revised method must be re-validated prior to use. If the modification is
				relatively minor, the validation studies may be focused on those parameters
				that have been affected.
(5)
				Validations must include linearity, precision, accuracy, LOD, LOQ, ULOL,
				carryover, selectivity/interference, and matrix effects. unless defined
				specifically below.
(6) The
				laboratory must characterize the linearity of a method based on replicate
				analysis (i.e., a minimum of three replicates at each concentration) of samples
				of at least six concentrations. The concentrations must be distributed above
				and below the cutoff for the test.
(7) The laboratory must characterize the
				precision of a method based on replicate analysis, at least 20 results total.
				Analysis must be at significant concentrations around the cutoff/decision point
				and expected range. At least three replicates at each concentration must be
				analyzed. Precision studies must be performed on multiple days and in multiple
				batches in order to assess intra-batch and inter-batch variability.
(8) The laboratory must characterize the
				accuracy (expressed as bias) of a method by calculating the percent difference
				between the analyzed sample results and the target concentrations. Accuracy
				studies must be performed on multiple days and in multiple batches to assess
				intra-batch and inter-batch variability.
(9) The laboratory must characterize the LOD
				of a method by a series of replicates with decreasing concentrations (i.e., a
				minimum of three replicates at each concentration). The LOD must be
				experimentally determined and supported by analytical data. The laboratory can
				choose to artificially set the LOD at the established LOQ if the LOQ is at
				least 25 percent below the decision point limit.
(10) The laboratory must characterize the LOQ
				of a method by a series of replicates with decreasing concentrations (i.e., a
				minimum of three replicates at each concentration). The LOQ of a method must be
				determined and supported by analytical data and must be at least 25 percent
				below the decision point limit.
(11) The laboratory must characterize the
				ULOL of a method by a series of replicates with increasing concentrations
				(i.e., a minimum of three replicates at each concentration). Laboratories may
				select a value at the upper end of the dynamic range for a method, but it must
				be determined and supported by analytical data.
(12) The laboratory must investigate the
				potential of carryover of a method from one sample to another during testing by
				analyzing highly concentrated samples followed by negative samples (i.e.,
				without the analyte of interest) and evaluate the negative samples for
				carryover. Positive samples that follow a sample at carryover concentrations
				must be reinjected or reextracted to eliminate carryover concerns.
(13) The laboratory must investigate the
				day-to-day precision using positive and negative samples assuring the
				ruggedness of the testing method provides good reproducibility over a period of
				at least five days.
(14) The
				laboratory must investigate the selectivity and interferences of a method by
				testing commonly encountered compounds and compounds that are structurally
				similar that could potentially interfere with the method at higher
				concentrations. Laboratories may accept manufacturer studies of immunoassay
				products if the study was performed using cannabis-focused compounds.
(15) The laboratory must investigate any
				possible matrix effect by evaluating the potential for components of the sample
				matrix to either suppress or enhance the ionization of the analytes of the
				com-pound(s) of interest and internal standard(s). Studies must include the
				evaluation of at least five different lots of products (i.e., flower from five
				different plants or from five different plant lots).
(16) When dilution of a sample is necessary
				to keep the result concentration within the range of linearity, the laboratory
				must conduct dilution integrity studies to document that the dilution does not
				affect the method's performance. These consist of precision/accuracy studies
				using samples at the dilution specified in the procedure.
(17) The laboratory must perform a parallel
				study when a new instrument or a new/revised procedure is implemented where
				results from the revised/new method or new instrument are compared to results
				from the existing method/instrument.
(18) The laboratory must perform a
				positive/negative differentiation study when validating a qualitative test by
				analyzing positive and negative samples that have been verified by a
				quantitative method to assess the assay's ability to differentiate positive and
				negative samples. The laboratory may analyze a combination of positive and
				negative controls, proficiency test (PT) samples or previously tested samples.
				The laboratory must analyze a minimum of five positive samples at differing
				concentrations and five negative samples (i.e., 10 results total).
(19) The laboratory must verify extraction
				efficiency assuring their method can sufficiently extract out the analyte of
				interest from the sample matrix.
(20) Records for validation and periodic
				reverification studies must be organized in a format to facilitate a
				comprehensive review and, at a minimum, the records must include:
(a) A stated purpose;
(b) Description of test method(s);
(c) Identity of the instrument(s) used for
				the study;
(d) A listing of the
				instrument parameters used for the study;
(e) A description of the study
				samples;
(f) A summary of the
				statistical data collected to characterize the assay;
(g) A discussion;
(h) A summary with conclusions; and
(i) All raw analytical data from the samples
				analyzed in the study.