Clinical Chemistry and Biomarkers
Clinical chemistry is the branch of laboratory medicine that measures chemical and biochemical constituents of blood, urine, and other body fluids to support diagnosis, prognosis, and monitoring. This area orients the reader to the major analyte groups measured in the clinical chemistry laboratory and to the concept of a biomarker as a measurable indicator of a biological state.
Definition
Clinical chemistry is the quantitative analysis of chemical substances in biological specimens; a biomarker is a characteristic that is objectively measured and evaluated as an indicator of normal biological processes, pathogenic processes, or responses to an exposure or intervention.
Scope
The area surveys the principal domains of clinical chemistry organised by physiological system and analyte class: electrolytes and fluid balance, renal function markers, hepatic function assessment, lipid and lipoprotein analysis, and cardiac biomarkers. It frames these as analytic and interpretive topics in laboratory medicine, covering what is measured and why it is informative, rather than offering clinical management instructions.
Sub-topics
Core questions
- What chemical constituents of body fluids carry diagnostic or prognostic information?
- How are reference intervals established and how does pre-analytical variation affect results?
- What distinguishes a useful biomarker from an incidental association?
- How do analytical interference and assay standardisation influence interpretation?
Key concepts
- Biomarker
- Reference interval
- Analytical sensitivity and specificity
- Pre-analytical variation
- Assay interference
- Method standardisation and harmonisation
- Diagnostic versus prognostic markers
Mechanisms
Clinical chemistry analytes are measured by methods including spectrophotometry, immunoassay, ion-selective electrodes, and mass spectrometry, each with characteristic sensitivity, specificity, and susceptibility to interference. Results are interpreted against reference intervals derived from defined populations, with attention to pre-analytical factors such as specimen collection, haemolysis, and timing. Standardisation and harmonisation efforts allow results to be compared across methods and laboratories, while interference studies characterise substances that can bias a measured value (rifai-tietz-2017; krasowski-2009).
Clinical relevance
Clinical chemistry results underpin much of routine diagnostic medicine, from electrolyte panels to cardiac biomarker testing. This entry describes how these measurements are generated and interpreted as part of laboratory evidence; it is a reference orientation and does not provide diagnostic thresholds or treatment guidance for individual patients.
Evidence & guidelines
Practice in clinical chemistry is shaped by reference textbooks such as the Tietz Textbook of Clinical Chemistry, and by analyte-specific recommendations from professional bodies — for example, laboratory practice recommendations for cardiac troponin use in acute coronary syndrome (wu-2018). Standardisation programmes and interference characterisation studies (krasowski-2009) support the comparability and reliability of measurements across laboratories.
Related topics
Seminal works
- rifai-tietz-2017
- wu-2018
Frequently asked questions
- What is the difference between clinical chemistry and a biomarker?
- Clinical chemistry is the laboratory discipline that measures chemical constituents of body fluids; a biomarker is any objectively measured characteristic used as an indicator of a biological state, and many clinical chemistry analytes serve as biomarkers.
- Why are reference intervals important in clinical chemistry?
- A measured value is interpreted relative to a reference interval derived from a defined population, so the same number can carry different meaning depending on the assay, the population, and pre-analytical conditions.