GLOSSARY

Serum Biomarker A biological indicator measured in serum after the sample's clotting process.

A recovery biomarker quantitatively relates to intake or expenditure under a specified balance model, whereas a concentration biomarker is influenced by absorption, metabolism and other factors. Predictive biomarkers use a calibrated relationship that may depend on the studied population. Distinguish intake biomarkers from markers of tissue status, function or disease. Blood, urine and tissue measurements answer different questions. Sampling conditions, recent exercise, hydration and inflammation can affect interpretation; no single biomarker provides a complete nutritional assessment or proves the cause of poor performance.

Nutrient status reflects intake, absorption, distribution, stores, losses and physiological demand. A normal blood concentration may not exclude depleted stores, while an abnormal result can have non-nutritional causes. Calcium in blood, for example, does not directly measure dietary calcium adequacy or skeletal reserves. Different nutrients require different assessment strategies. Select tests for a defined clinical question and interpret them with symptoms, diet, relevant disease and sampling conditions instead of ordering a broad panel and assuming every number is a performance target.

Laboratory markers provide information within a clinical context rather than a complete nutrition diagnosis. Albumin and prealbumin are affected by inflammation, fluid balance, organ function and other processes, so they should not be interpreted as direct isolated measures of protein intake or muscle mass. A reference interval is not automatically the optimal target for an athlete. Combine relevant tests with intake, physical findings, symptoms and trends, and consider the method and timing before attributing a result to diet alone.

Accuracy concerns closeness to an appropriate reference, while precision concerns repeatability; consistent measurements can still be systematically wrong. Validity asks whether a method supports its intended interpretation, and reliability asks how consistently it performs. Reporting error can reflect memory, burden, food omission or social pressure. An implausible estimate should prompt review rather than an accusation. Calibration may reduce specific errors under defined assumptions, but it does not turn every self-report into an exact measurement of an athlete's habitual intake.

Choose a dietary assessment method according to the question, population and resources. A recent intake record can explore meal timing around training; a frequency questionnaire can describe longer-term patterns. Neither automatically establishes exact habitual intake. Combine food details with training, access, symptoms, medication and relevant measurements. Explain uncertainties and what the method cannot answer. Good assessment produces a decision that can be reviewed, rather than an impressive nutrient report whose apparent precision exceeds the quality of the information collected.

A nutrition care record should explain the assessment, interpretation, agreed plan, responsible professionals and follow-up criteria. Separate reported information from measured findings and clinical judgments. Record relevant units, dates, methods and changes so that another practitioner can understand the decision. Seek consent for sharing sensitive information and limit access appropriately. A referral should communicate the specific concern and urgency rather than only a broad label. In sport, documentation should support continuity of care while protecting health information from inappropriate use in coaching or selection.