OncoFirm™ / Research / Laboratory medicine
Pillar guide · Laboratory medicine
What Is Biochemical Diagnostics? How Laboratory Tests Measure Health, Disease and Cancer Markers
Behind almost every diagnosis is a measurement: a glucose level, a liver enzyme, a hormone, a cancer marker. Biochemical diagnostics is the science of making those measurements accurately and turning them into decisions. This guide explains what it measures, how a sample becomes a trustworthy result, how results are interpreted and regulated, and how quantitative testing is moving from central laboratories to the point of care.
At a glance
Also called
Clinical chemistry or clinical biochemistry
What it measures
Electrolytes, metabolites, enzymes, proteins, hormones, lipids, drugs and tumor markers
Where
Central laboratories, hospital labs and point-of-care settings
Global gap
About 47% of people have little or no access to diagnostics (Lancet Commission)
OncoFirm™ focus
Quantitative, traceable protein measurement at the point of care (in development)
On this page
Key points
Why biochemical diagnostics matters
47%of the world's population has little or no access to diagnostics
19%of people in low and lower-middle income countries can get basic tests in primary care
1.1Mpremature deaths a year could be avoided by closing the gap for six conditions
Figures are from the Lancet Commission on diagnostics (2021).
Definition
What is biochemical diagnostics?
Biochemical diagnostics, also called clinical chemistry or clinical biochemistry, is the branch of laboratory medicine that measures chemical and biochemical substances in body fluids, mainly blood and urine, to detect disease, assess risk, guide treatment and monitor health.
The principle is simple: illness changes body chemistry in measurable ways. Damaged liver cells release enzymes, failing kidneys let creatinine accumulate, a heart attack releases troponin, and some tumors shed proteins such as CEA or PSA. Measuring these changes accurately, and knowing what they mean, is the work of biochemical diagnostics.
It sits alongside other diagnostic disciplines: hematology (blood cells), microbiology (infections), molecular diagnostics (DNA and RNA), pathology (tissue) and imaging. Modern care usually combines several.
What it measures
The main things biochemical tests measure
| Category | Examples | What it can indicate |
|---|---|---|
| Electrolytes and minerals | Sodium, potassium, calcium | Fluid balance, kidney and heart rhythm risks |
| Metabolites | Glucose, creatinine, urea, bilirubin | Diabetes, kidney function, liver function |
| Enzymes | ALT, AST, ALP, lipase, CK | Liver, pancreas or muscle injury |
| Proteins | Albumin, CRP, troponin | Nutrition, inflammation, heart muscle injury |
| Hormones | TSH, insulin, hCG | Thyroid disorders, metabolic disease, pregnancy |
| Lipids | Cholesterol, triglycerides | Cardiovascular risk |
| Glycated proteins | HbA1c | Average blood glucose over about three months |
| Tumor markers | CEA, PSA, AFP, CA-125 | Cancer monitoring and, in specific settings, risk assessment |
| Drugs and toxins | Therapeutic drug levels, toxicology | Dosing, overdose, poisoning |
Tumor markers are covered in depth in what are cancer biomarkers? and tumor antigen detection.
How it works
From sample to result: the total testing process
A result is only as good as every step that produced it. Most laboratory errors happen before the sample reaches the analyzer, during ordering, collection, labelling or transport.
- Pre-analytical: choosing the right test, patient preparation (for example fasting), correct tube, labelling, and timely transport and storage.
- Analytical: calibration against traceable reference materials, measurement on the analyzer and quality-control checks before release.
- Post-analytical: reporting with units and reference intervals, flagging critical values, interpretation and clinical action.
Techniques
Core measurement techniques
- Photometry and spectrophotometry: measure light absorbed or emitted by a reaction; the workhorse of routine chemistry for glucose, enzymes and many others.
- Ion-selective electrodes: measure electrolytes such as sodium and potassium electrically.
- Immunoassays: use antibodies to capture specific proteins or hormones. Formats include ELISA, chemiluminescence, fluorescence and lateral flow.
- Chromatography and mass spectrometry: separate and identify molecules with high specificity; used for drugs, hormones, metabolic disorders and reference methods.
- Dry chemistry and point-of-care devices: compact formats such as test strips and cartridges read by small instruments.
- Emerging approaches: metabolomics and proteomics profile hundreds of molecules at once, and algorithms combine several markers into one result.
For immunoassay formats used at the point of care, see how lateral flow assays work and fluorescent vs gold nanoparticle assays.
Interpreting results
How biochemical results are interpreted
- Reference intervals describe the central 95% of a healthy population, so about 1 in 20 healthy people fall outside them. A slightly abnormal value is not automatically a problem.
- Decision limits are thresholds set by clinical evidence rather than population ranges. For example, an HbA1c of 6.5% or higher is used to diagnose diabetes, and myocardial infarction is defined using the 99th-percentile upper reference limit for cardiac troponin.
- Trends are often more informative than a single value, provided the same method is used over time.
- Context matters: age, sex, pregnancy, medications, timing and other results change what a number means.
- Critical values such as dangerously high potassium are phoned to clinicians immediately.
For patients: lab reports are designed to be read by your care team alongside your history and examination. If a result is flagged, ask your clinician what it means for you rather than relying on the reference range alone.
Quality and regulation
How accuracy is protected
- Metrological traceability: calibrators are linked to higher-order reference materials and methods, many listed by the Joint Committee for Traceability in Laboratory Medicine (JCTLM), so results agree across laboratories and over time.
- Internal quality control and external quality assessment: laboratories run control samples every day and take part in proficiency-testing schemes that compare them with peers.
- Accreditation: ISO 15189 sets international requirements for the quality and competence of medical laboratories.
- U.S. oversight: under CLIA, laboratory testing is categorized as waived, moderate or high complexity. Commercial test kits are regulated by the FDA as in vitro diagnostic devices. In 2025 a federal court vacated the FDA's rule on laboratory-developed tests, and the FDA formally rescinded it in August 2025.
Point-of-care testing
Bringing biochemical testing closer to patients
Point-of-care tests are performed near the patient, in a clinic, pharmacy or community setting, with results in minutes. Familiar examples include glucose meters, HbA1c analyzers and pregnancy tests. The WHO Model List of Essential In Vitro Diagnostics, now in its fifth edition, includes tests intended for settings without a laboratory.
The Lancet Commission on diagnostics found that only about 19% of people in low and lower-middle income countries have access to basic tests in primary care, and called for more point-of-care testing to close the gap. The challenge is to deliver laboratory-grade reliability in a simple format: traceable calibration, built-in controls and clear, quantitative results.
Role in cancer
Biochemical diagnostics in cancer care
Protein tumor markers are a biochemical tool. CEA is used to monitor colorectal cancer, PSA in prostate cancer detection and follow-up, AFP in liver cancer surveillance and germ cell tumors, and CA-125 in ovarian cancer. Their greatest value is usually in monitoring and in defined high-risk groups, not in screening the general population.
Because no single marker is perfect, research increasingly combines several markers with other data, as discussed in AI-driven biomarkers and causes of high AFP.
OncoFirm™ approach
Laboratory-grade biochemistry, designed for the point of care
OncoFirm™ applies the principles on this page, traceable calibration, quantitative measurement and built-in quality checks, to protein cancer biomarkers that are usually measured in central laboratories. The aim is to make reliable, repeatable measurement available where patients are first seen.
Quantitative immunoassay
A fluorescent lateral flow immunoassay designed to report concentrations in ng/mL, not just a visible line. Platform
Traceable calibration
Designed ranges of 1–100 ng/mL for CEA and 0.5–50 ng/mL for PSA, with planned traceability to WHO international standards (NIBSC 73/601 and 17/100).
Results in minutes
A handheld reader with a result-time target of 20 minutes or less, capturing quality flags with every result. Digital readers
A growing menu
One reader and strip design intended to support additional protein markers over time. Test menu
OncoFirm™ assays and reader are in development, have not been cleared or approved by the FDA or any other regulatory authority, and are for research use only. Designed ranges and result time are development targets.
FAQ
Frequently asked questions
What is biochemical diagnostics?
Biochemical diagnostics, also called clinical chemistry or clinical biochemistry, is the part of laboratory medicine that measures chemicals, proteins, enzymes, hormones and other substances in body fluids such as blood and urine to help detect disease, assess risk, guide treatment and monitor health.
What is the difference between biochemical and molecular diagnostics?
Biochemical diagnostics measures the substances the body makes or uses, such as glucose, enzymes and proteins. Molecular diagnostics analyzes genetic material, DNA or RNA, for example to detect mutations or pathogens. Many conditions are best assessed by combining both.
What is a reference interval?
A reference interval is the range of results found in the central 95% of a healthy reference population. By definition, about 1 in 20 healthy people will fall outside it, so a result just outside the range is not automatically abnormal and must be interpreted in context.
Can biochemical tests diagnose cancer?
Biochemical tumor markers such as CEA, PSA, AFP and CA-125 support cancer care, mainly for monitoring treatment and recurrence and, in specific settings, for risk assessment. With few exceptions they are not used alone to diagnose cancer; imaging and tissue biopsy confirm the diagnosis.
Are point-of-care tests as accurate as laboratory tests?
It depends on the test and how it is used. Well-designed, validated point-of-care tests can approach laboratory performance for specific purposes, but they must meet defined accuracy requirements, use traceable calibration and be operated with quality control.
How does OncoFirm™ relate to biochemical diagnostics?
OncoFirm™ is developing quantitative fluorescent immunoassays, a type of biochemical test, designed to measure protein biomarkers such as CEA and PSA at the point of care with laboratory-style calibration. These tests are in development and are not cleared or approved by the FDA.
Keep reading
Related guides
Sources
References
- Fleming KA, Horton S, Wilson ML, et al. The Lancet Commission on diagnostics: transforming access to diagnostics. The Lancet. 2021;398(10315):1997–2050. www.thelancet.com/journals/lancet/article/PIIS0140-6736(21)00673-5/fulltext
- World Health Organization. WHO Model List of Essential In Vitro Diagnostics (fifth edition). edl.who-healthtechnologies.org/
- U.S. Code of Federal Regulations. 42 CFR Part 493: Laboratory requirements (CLIA). www.ecfr.gov/current/title-42/chapter-IV/subchapter-G/part-493
- International Organization for Standardization. ISO 15189:2022 Medical laboratories: requirements for quality and competence. www.iso.org/standard/76677.html
- Joint Committee for Traceability in Laboratory Medicine (JCTLM), BIPM. www.bipm.org/en/committees/jc/jctlm
- Thygesen K, Alpert JS, Jaffe AS, et al. Fourth Universal Definition of Myocardial Infarction (2018). Circulation. 2018;138:e618–e651. doi.org/10.1161/CIR.0000000000000617
- American Diabetes Association. Understanding A1C: diagnosis. diabetes.org/about-diabetes/a1c
- The FDA Law Blog (Hyman, Phelps & McNamara). FDA formally rescinds the LDT final rule following defeat in court. August 2025. www.thefdalawblog.com/2025/08/fda-formally-rescinds-the-ldt-final-rule-following-defeat-in-court/
About this article. Written by the OncoFirm™ Scientific Team from international standards, regulatory sources and peer-reviewed publications, all linked above. This article is for education and is not medical advice; it cannot be used to interpret an individual test result. OncoFirm™ assays are in development, have not been cleared or approved by the FDA and are not available for sale.
Partner on point-of-care biochemical testing
Laboratories, clinicians and global-health partners interested in quantitative, traceable testing outside the central laboratory can reach the OncoFirm™ team. Collaboration inquiry