Establishing quality assurance criteria for serial dilution operations on liquid-handling equipment.
Since the advent of high-throughput screening (HTS) in the early 1990s, parallel multichannel liquid handlers have become a mainstay in every drug discovery setting. Although several peer-reviewed publications have discussed methods and criteria for stamping multiwell copies, there is very little information about establishing a standard operating procedure (SOP) for standard (microliter-level) serial dilutions of compounds used in dose-response experiments. The authors discuss the 4 main criteria any serial dilution process must pass (accuracy, precision, fold dilution, and outliers) and the process for establishing thresholds for all of these values in a compound management or biological screening laboratory. The thresholds need to be both low enough to be acceptable from a biological potency variability perspective and high enough to allow the instruments to pass the quality assurance (QA) analysis on a regular basis. In this article, the authors suggest suitable thresholds arrived at by a variety of methods, including trend analysis of QA data, survey questionnaire from the main stakeholders (screening scientists, chemists), and published criteria for single-shot stamping. A mathematical analysis of the effect of threshold values on estimated XC(50)s was performed to ensure that the variability introduced by the serial dilution step is within acceptable overall variability limits.
Popa-Burke
Ioana
I
GlaxoSmithKline, Sample Management Technologies, Research Triangle Park, North Carolina 27709-3398, USA. ioana.g.popa-burke@gsk.com
Lupotsky
Brian
B
Boyer
Joseph
J
Gannon
William
W
Hughes
Rob
R
Kadwill
Paul
P
Lyerly
Donald
D
Nichols
Jason
J
Nixon
Elizabeth
E
Rimmer
Darren
D
Saiz-Nicolas
Isabel
I
Sanfiz-Pinto
Beatriz
B
Holland
Sue
S
D055808:Drug Discovery / Q000295:instrumentation / Q000379:methods / Q000592:standards; D007201:Indicator Dilution Techniques / Q000592:standards; D008163:Luminescent Measurements / Q000592:standards; D046210:Microfluidic Analytical Techniques / Q000295:instrumentation* / Q000379:methods / Q000592:standards*; D008954:Models, Biological; D011786:Quality Control; D012015:Reference Standards; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013048:Specimen Handling / Q000379:methods / Q000592:standards*