The Nutritional Biomarker Laboratory develops and applies novel nutritional and related biomarker assays for use in human research. On occasion, in the development of new assays, we require blood or other biological samples to develop and test analytical methods. Whilst biological material can be purchased commercially, we are limited in what we can do with this material since it is (a) often from a single donor and (b) collected using protocols that may not be compatible with specific assays.

We therefore require human biological samples that have been collected, processed and stored in a specified manner e.g. into blood tubes with specific anticoagulants or using specific sample processing protocols or specific sample types, such as dried blood spots or other capillary blood sampling.

Biological material collected under this ethical application will be used in three areas:

1. Development of new assays. Standards and single-source commercial blood can be used in the initial development stages but full development requires samples from multiple donors. Assays using different sample types may also be investigated, e.g. the use of dried blood spots compared to venous blood. Examples of planned method development work include the measurement of non-nutritive sweeteners in urine and the measurement of vitamin D, retinol and folate in dried blood spots.
2. Evaluation of new and existing assays to determine precision, sensitivity, specificity and robustness, e.g. sample type compatibility comparing lithium-heparin plasma and EDTA plasma. Sample stability at different storage formats (liquid, dried on paper) and temperatures (e.g. refrigerator, -20°C freezer, -80°C freezer, ambient temperature etc.) may be investigated. Examples include the stability of vitamin D, retinol and folate in dried blood spots.
3. Monitoring of assay performance. Biological samples are required to prepare quality control (QC) material for routine analysis to monitor intra- and inter-assay imprecision and for troubleshooting using well-characterised samples. Where possible, we use commercially available material for QC but these may not offer suitable concentrations or specific sample types required for some assays. Examples include the use of washed red blood cells for the measurement of thiamine and riboflavin status for which commercial QC material is not available.

• Participant information sheet (pdf)
• Sample consent form (pdf)