TABLE 4.
Scientific and logistic considerations that are part of NHANES nutritional biomarker selection and interpretation
| Category for consideration | Questions to be considered |
| Biomarker selection—scientific issues (quality and validity of a biomarker) | What does the biomarker represent (short-term status, long-term status, intake, function)? |
| Is the sensitivity or specificity of the biomarker appropriate for the intended purpose? | |
| Are multiple biomarkers per nutrient needed to improve sensitivity or specificity? | |
| What are relevant biological confounders? | |
| What is the biological variation of the biomarker? | |
| Has the biomarker been qualified for clinical or public health use? | |
| Biomarker selection—logistic issues (methodologic issues of data generation) | Can an appropriate specimen be collected, processed, and stored? |
| What preanalytic factors need to be considered? | |
| Is a reliable and validated laboratory method available? | |
| Is the laboratory method precise enough relative to the biological variation? | |
| Can the laboratory method handle the sample throughput in a reasonable time? | |
| Are resources available for specimen collection and laboratory analysis? | |
| Biomarker interpretation—scientific issues (methodologic issues of data analysis) | Are reference intervals or cutoffs available? |
| Are cutoffs or reference intervals relevant to groups or individuals of interest? | |
| Do any exclusion criteria need to be applied? | |
| What sample sizes are required to assess status in subgroups of the population? | |
| Biomarker interpretation—logistic issues (quality and validity of data) | Is sufficient information available to judge the quality of the data? |
| Have laboratory methods been standardized to yield comparable results? | |
| Have laboratory methods changed over time? | |
| Is data adjustment needed for comparability? |