Pooled sample analysis

Riad LE, Chan KK, Sawchuk RJ. Determination of the relative formation and elimination clearance of 2 major carbamazepine metabolites in humans—comparison between traditional and pooled sample analysis. Pharm Res 1991 8(4) 541—543. 

Jolly, R. A. et al., Pooling Samples Within Microarray Studies A Comparative Analysis of Rat Liver Transcription Response to Prototypical Toxicants, Physiol. Genomics, 22, 346, 2005. 

High-throughput laboratories have turned to assay automation, N-in-one (sample pooling) analysis strategies, and elaborate set-ups for parallel chromatography30 33 to increase capacity and decrease turn-around time. Despite the relatively fast speed of HPLC/MS, this step still creates a bottleneck in ADME work flow. Xu et al.32 reported a fast method for microsomal sample analysis that yields 231 data points per hour using a complex eight-column HPLC/MS set-up. 

Rapid, accurate SNP validation can be carried out using a sample-pooling technique—allele frequency—that rapidly screens and confirms the presence of an SNP and its allelic frequency in patient populations. Conventional technologies typically analyze each SNP in each individual of the population in question, and individual results are then consolidated to yield the overall SNP allele-frequency distribution. MS-based technology is able to determine SNP allele frequencies with high precision in pooled samples, thereby replacing hundreds of individual measurements with one consolidated analysis. To that end, DNA is isolated, purified, and quantitated. A pool of DNA is formed from a high number of different individuals, amplified, and mass measured. 

With the advent of API sources, LC/MS/MS allows the facile development of quantitative methods that are sensitive, selective, robust, and amenable to the rapid analysis of a majority of small molecules. In order to achieve high-throughput bioanalysis in support of pharmacokinetic studies, many approaches have been reported utilizing automated sample preparation and reducing analysis time by pooling samples, parallel analysis, and fast chromatography. 25,26,152,153... 

In the pooled estimate, we calculate the sample variance for each group (each column of data in a one-way analysis). Then we weigh each of these estimates by its degrees of freedom to obtain a pooled sample variance. For any column i, the sample variance is ... 

Pacek P, Sajantila A, Syvanen AC. Determination of allele frequencies at loci with length polymorphism by quantitative analysis of DNA amplified from pooled samples. PCR Methods Appl 1993 2 313-317. 

Prior to sample analysis, a test batch is required if (1) STD and QC pools need to be qualified, (2) there has been a significant lapse in time since any previous analysis, (3) the scientist does not have documentation with the assay or a similar assay. The test batch should contain minimally low, medium, and high QC at six replicates. Dilution QC samples may be included if dilutions are expected during sample analysis. The acceptance of PSAE is the same as described in intraassay precision and accuracy. 

Urinalysis Urine samples should be collected for analysis from all nonrodents, from 10 rats, and genders of all groups, using preferably the same rats at the same intervals. The following determinations should be made, either on individual animals or on a pooled sample/gender/group for rodents Appearance,... 

At low sweat rates, sweat electrolyte concentration decreases and the opportunity for sample evaporation is increased. To ensure a valid result, the average sweat rate should exceed Ig/mVmin. The minimum acceptable volume or weight depends on the size of the electrode and stimulation area, the type and size of collecting devices, and the length of time the sweat is collected. If a laboratory deviates from standard parameters, the minimum acceptable sweat volume or weight will change. The stimulation and/or collection requirement applies to each site independently, so insufficient samples must not be pooled for analysis. 

Data in these studies were generated from a so-called giant rat study in our laboratory. Animals were sacrificed to obtain serial blood and tissue samples. Each point represents the measurement from one individual rat and data from all these different rats were analyzed together to obtain a time prohle as though it came from one giant rat. A naive pooled data analysis approach was therefore employed for all model fittings using ADAPT II software (21). The maximum likelihood method was used with the variance model specified as V(a, 6, h) = (j Y(d, where V a, 9, ti) is the variance for the ith point, Y 6, t,) is the ith predicted value from the dynamic model, 9 represents the estimated structural parameters, and oi and 02 are the variance parameters that were estimated. 

Samples must be weighed, whet, and dry. Before analysis, the samples have to be homogenized and extracted, and the pesticide must be concentrated and isolated. If the samples are too large, a subsample must be taken. Much effort must be carried out to make this representative. Sometimes the final steps of the analysis are too expensive, or the samples are too small to be individually analyzed. Pooled samples may then be made — in this case, representative individual samples are mixed and treated as one. 

Hing, J.P., Woolfrey, S.G., Greenslade, D. and Wright, P.M.C. Is mixed effects modeling or naive pooled data analysis preferred for the interpretation of single sample per subject toxicokinetic data. Journal of Pharmacokinetics and Pharmacodynamics 2001b 28 193-210. 

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