⚕️ Educational content only. This article introduces clinical biochemistry as a biomedical science discipline. It is not medical advice.
Clinical biochemistry — also known as chemical pathology or clinical chemistry — is the branch of laboratory medicine concerned with measuring biochemical substances in body fluids, primarily blood and urine. It encompasses a vast range of analytes, from basic electrolytes and metabolites to hormones, enzymes, proteins, and drugs. Clinical biochemistry laboratories are among the highest-volume departments in any hospital, processing thousands of tests per day.
Key Takeaways
- Clinical biochemistry measures metabolites, enzymes, hormones, and proteins to support diagnosis and disease monitoring.
- Core tests include renal function (U&E, creatinine), liver function (ALT, ALP, bilirubin, albumin), thyroid function, glucose, and lipids.
- Modern biochemistry labs use high-throughput automated analysers and quality control processes to deliver rapid, accurate results.
- Clinical biochemists and biomedical scientists work closely with clinicians to interpret results and advise on appropriate testing.
What Does Clinical Biochemistry Cover?
Clinical biochemistry encompasses an enormous range of analytes. Core disciplines within it include: routine chemistry (electrolytes, urea, creatinine, glucose, liver enzymes, lipids); endocrinology (thyroid hormones, cortisol, HbA1c, sex hormones, insulin); therapeutic drug monitoring (digoxin, vancomycin, tacrolimus, lithium); toxicology (paracetamol, salicylate, ethanol, drug screens); proteins and immunology (albumin, CRP, immunoglobulins, serum protein electrophoresis); and point-of-care testing (blood gas, bedside glucose, troponin). Many labs also cover tumour markers and bone biochemistry.
Core Test Panels
Urea and Electrolytes (U&E)
The U&E panel measures sodium, potassium, urea, creatinine, and bicarbonate. It assesses renal function and electrolyte balance and is one of the most frequently requested panels in clinical medicine. Estimated GFR (eGFR) is calculated from creatinine, age, and sex using the CKD-EPI equation and is reported alongside creatinine to classify chronic kidney disease.
Liver Function Tests (LFTs)
LFTs measure bilirubin (total and direct), ALT (alanine aminotransferase), AST (aspartate aminotransferase), ALP (alkaline phosphatase), GGT (gamma-glutamyl transferase), and albumin. Together they distinguish hepatocellular damage (raised transaminases) from cholestatic disease (raised ALP/GGT/bilirubin) and assess synthetic function (albumin, prothrombin time).
Glucose and HbA1c
Fasting and random glucose tests diagnose diabetes mellitus and hypoglycaemia. HbA1c reflects average glycaemia over the preceding 2–3 months (the lifespan of a red cell) by measuring the proportion of haemoglobin glycated at the N-terminal valine of the beta chain. It is used for diabetes diagnosis (≥48 mmol/mol / ≥6.5%) and monitoring.
Analytical Methods in Clinical Biochemistry
Modern biochemistry laboratories use large automated analysers (e.g. Roche cobas, Abbott Architect, Siemens ADVIA) that can process hundreds of samples per hour using photometric, turbidimetric, immunoassay, and ion-selective electrode methods. Internal quality control (IQC) and external quality assurance (EQA) schemes ensure result accuracy. Point-of-care (POC) analysers extend testing to wards, ICUs, and emergency departments, providing rapid turnaround for blood gases, electrolytes, lactate, glucose, and cardiac biomarkers.
Careers in Clinical Biochemistry
Clinical biochemists (consultants in chemical pathology) are medically qualified doctors specialising in laboratory medicine. Biomedical scientists (BMS) with specialisation in clinical biochemistry perform day-to-day laboratory analysis, quality control, and analytical troubleshooting. Clinical scientists (non-medical) provide specialist interpretation and service development. All roles require HCPC registration (in the UK) and ongoing CPD. It is an intellectually rich discipline spanning basic science, clinical medicine, and analytical technology.
References
- Association for Clinical Biochemistry and Laboratory Medicine. What is clinical biochemistry? acb.org.uk
- Marshall WJ, Lapsley M, Day AP, Ayling RM. Clinical Biochemistry: Metabolic and Clinical Aspects. 3rd ed. Churchill Livingstone; 2014.
- NHS Health Careers. Clinical biochemist. healthcareers.nhs.uk