Internal Quality Assurance Programs
Truesdail Laboratories, Inc. continually strives to achieve excellence in performance by incorporating a comprehensive Quality Control Program for its routine laboratory practices. The goal of our Internal Quality Program is to introduce into our sample screening process, quality control samples at a rate of 5 to 10%. Performance of all quality control samples (blanks, standards, internal standards, etc.) along with our clients samples, undergo a thorough review process. Blind control samples are monitored and tracked to ensure ongoing lab proficiency, as well as to identify potential points of improvement in our analytical processes.
Internal QC Procedure Summary
Drugs are selected for Internal Blind QC samples in order to challenge the Direct Instrumental methods performed as well as to challenge the various immunoassay screens in use. The spike levels of various drugs are modified to accommodate the difference in sensitivities between immunoassay and direct instrumental methods. The drug concentrations utilized routinely approach the detection limit of the analytical methods. The group of QC samples for a given week may contain the following:
- One or more drugs at Direct Instrumental detection levels for serum. Instrumental detection levels for each drug are determined by limit of detection studies for the methods in use.
- One or more drugs at Direct Instrumental detection levels for urine.
Records on the performance of both the Direct Instrumental and the immunoassay screening results are monitored as part of Truesdail’s QA/QC program. The results are evaluated by the QA/QC Manager, Technical Director, and Chief Science Officer and any actions deemed necessary to improve the screening process are implemented as part of Truesdail’s Continual Improvement Program.
Specific Internal Quality Control (QC) Activities
Direct Instrumental Screening
Internal QC samples are added to each set of samples. A set usually consists of the samples shipped to the Lab from one day of racing. The internal QC samples are spiked, extracted and analyzed along with the client samples by LC/MS or GC/MS. The purpose of the QC samples is to ensure that the drugs can successfully be identified with the instruments and methods we have in place. It is also a safeguard to make sure that data isn’t released to the clients until our quality control requirements are satisfied for each set.
Internal standards, typically deuterated standards of common drugs from different classes of drugs, are also added to samples to be screened in addition to control blood and urine samples. The recovery of the internal standards are control charted to verify that the extraction and preparation process and instrumental analysis are functioning properly.
Both matrix (blood or urine) and solvent blanks are analyzed with each batch of samples. Running these blank samples verifies that no inadvertent contamination occurred during the drug extraction and preparation process.
Liquid Chromatography / Mass Spectroscopy (LC/MSn )
The LC/MS system is evaluated and calibrated using a mixture of compounds to characterize its performance. This mixture is used daily, if poor performance is suspected, or after maintenance. The daily check for the LC/MS consists of obtaining satisfactory spectra of the drug(s) being sought on the day of analysis. Confirmation of drug samples will include the quality control of drug calibration mixtures, negative and positive control samples, and appropriate solvent and system blanks.
Gas Chromatography/Mass Spectroscopy (GC/MS)
When suspect samples are submitted for GC/MS confirmation/identification, the GC/MS instrument is tuned to decafluorotriphenylphosphine (DFTPP) to validate the instrument’s proper operation, after which a solvent blank, negative and positive control samples, standard solution of the suspect drug, and the suspect sample are examined. The spectra of all samples are then examined and recorded.
Five to eight wells are used for calibration standards. Quality control is monitored by analysis of standards used in each plate. These standards consist of a control negative and several standard concentration levels spiked into known blank urine. One of the QC standard levels is spiked at the threshold for the specific drug being tested. Blind quality control samples are run at a frequency of 5 to 10%. This assures that immunoassay systems meet specifications for drug detection.
High Pressure Liquid Chromatography (HPLC)
Quality control samples, at varying concentrations of the specific analytes, are analyzed along with official blood or urine samples. Additionally, check standards (spiked samples) are quantitatively analyzed along with official samples to verify extraction efficiency and proper instrument function. The deviation range of our check standards (at the regulatory level) for a particular analyte must be within ± 10%. These check standards are run after every 10 samples and if the acceptance criteria is not met, the samples are re-extracted and re-analyzed.