MS-QA_06-2019 rev5

ANSI/AARST MS-QA 2019 9 Radon Measurement Systems Quality Assurance Requirements For All Methods 3 REQUIREMENTS FOR ALL METHODS Informative Advisory— It is important to recognize that usually quality assurance (QA) practices result not in the identification of out-of-control processes, but in the continued documentation of stable, within-limits operations. Only with such documentation can the validity of measurement results be defended. 3.1 Quality Assurance Required Each qualified professional (QP) and analysis service provider shall be responsible for developing, documenting and implementing their own procedures for defensible quality control (QC) processes and assessments within the context of their operation’s quality management system. The requirements herein include minimum QC requirements that must be included in an annually reviewed and updated quality assurance plan (QAP). 3.1.1 QC Checks QC checks are to be conducted, recorded and evaluated using time sequence control charts so that processes can be reviewed for internal quality improvement with documentation available to credentialing authorities subject to confidentiality agreements. Note—Examples of time sequence control charts are provided in the MS-QA Companion Guidance. 3.1.2 Training All radon measurement methods have specific advantages and limitations, and each device type and configuration have unique procedures for use, along with critical device-specific QC control procedures. Therefore, QAP-documented, device-specific training is required to performmeasurements in accordance with this standard. A record of training, e.g., certificate(s) or similar, must be maintained by the trainee and, if applicable, by the trainee’s organization. 3.1.3 Chain of Custody As with the transport of any sample or device to be analyzed, chain-of-custody procedures are to be implemented with documentation of times, conditions, locations and personnel. The exact test location including building address, room and floor and all other factors relevant to the analysis or interpretation are to be recorded, stored and relayed to the analyst as appropriate. 3.1.4 Data Validation Measurement results are defensible as valid when they are bracketed in time by applicable within-limit QC results. The record of QC checks shall be part of the quality system documentation and available to auditors or other credentialing authorities, subject to confidentiality agreements. Valid data produced by continuous radon monitors must similarly be bracketed in time by documented, within-limits QC checks, and those that record automatic instrument checks, data flagging and reporting for unusual results provide increased assurance for data validity. 3.1.5 Reporting When opinions and interpretations are included, the laboratory or field professional’s report shall document the basis upon which the opinions and interpretations have been made. Opinions and interpretations, including initials and date, shall be clearly marked as such in a test report. 3.1.6 Quality System Every QP is to operate within a quality system , which is documented in a QAP, as defined in this standard. Documentation shall be available to auditors and credentialing authorities, subject to confidentiality agreements.