Scientific Concept of the National Cohort (status ... - Nationale Kohorte

A.5 Methods for quality assurance and quality control
The influence of temperature, storage time, preservatives and additives to the collection
tubes, and repeated rounds of freezing and thawing on the sample quality will also be
tested during the feasibility studies using appropriate and sensitive markers. To guarantee
temperature stability over time, the temperature of all freezers will be documented daily. The
number of stored aliquots and all deviations from the standardized protocol will be documented
in a central database. Furthermore, a contingency plan will ensure sample integrity
over the intended lifetime of the study, including storage solutions designed to assure that
conditions are maintained (e.g., mechanical breakdown of the refrigeration plant, the robotics
system, or the electrical supply).
The procedure for sample aliquot retrieval will be established according to predefined criteria
and follow specific SOPs. Furthermore, sample movements will be tracked and logged
in a central database using the bar codes of each container.
Deviations from any of the standardized protocols will be documented in the central database
and therefore be readily available for examination by any unit involved in quality
management.
Novel technologies that arise during the recruitment or follow-up phases of the study will be
tested in parallel with existing methods. Only if old and new technologies yield comparable
data will we consider replacing existing methods.
A subset of clinically relevant laboratory data will be provided to study participants within
several weeks of their visit at the study center. Clinical parameters will be analyzed in certified
laboratories associated with the study centers. Measurements between the clinical
laboratories will be verified to determine interlaboratory variability.
If necessary, the epidemiologic planning committee and competence units will define
whether certain groups of participants will need to be excluded from the study. To identify
appropriate exclusion criteria, specific questions will be included in the core questionnaire.
A.5.6.2 quality control of biological specimens
To monitor adherence to the SOPs, experts selected by the competence unit on biomaterials
will visit the study centers at regular intervals. The competence unit is also accredited
to authorize deviations from SOPs, if necessary. All study centers will be visited by external
quality management once each year to ensure adherence to the SOPs and to certify the
examiners and technicians on site. Furthermore, the examiners und technicians will be
retrained and recertified once per year to ensure adherence to the SOPs over time. If quality
disparities are identified in biological samples collected by a certain individual, reasons
which could explain such variation will be ascertained and used to retrain that particular
technician. Newly hired personnel will receive the same training procedure as the core staff.
Replicate measurements are used in a number of settings. During the feasibility and pilot
studies, they are used to test the impact of time and storage conditions on sensitive biomarkers
and to test different verification procedures within the study centers or clinical laboratories.
During the main study, replicate measurements are used to identify data errors.
Replicate measurements will be appropriately documented and analyzed. Local accuracy
checks will be used to detect missing, incorrect, interchanged, or nonclassifiable parameters.
Interchanged or nonclassifiable biological specimens or parameter values will be discarded.
Conspicuous values will be checked promptly and, if necessary, will be discussed
with the clinical laboratory responsible for that particular value.
The liquid handling equipment will be calibrated and inspected regularly to ensure accuracy
and precision of the robotics procedures. The precision in preparing aliquots will be checked
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A.5