Biochemistry Tests Explained: Organ Function, Ranges & What Results Mean
What Is Biochemistry?
Clinical biochemistry is the highest-volume section of the modern laboratory. One tube of blood can report on the liver, kidneys, heart risk, sugar, thyroid, bones and nutrition at once.
Most chronic diseases announce themselves here first. Diabetes, fatty liver, kidney disease and high cholesterol begin as quiet shifts in biochemistry values.
That is why panels like LFT, RFT and lipid profile appear on almost every health check. They catch problems while they are still reversible.
Biochemistry Tests List
| Panel / Test | What It Measures |
|---|---|
| Blood Sugar & HbA1c | Fasting, random and 2–3 month average glucose (HbA1c) |
| Liver Function Tests (LFT) | ALT/SGPT, AST/SGOT, ALP, GGT, bilirubin, albumin, total protein |
| Lipid Profile | Total cholesterol, LDL, HDL and triglycerides |
| Kidney Function Tests (RFT) | Urea, creatinine, eGFR and electrolytes (sodium, potassium) |
| Thyroid Profile | TSH, free T4 and T3 |
| Cardiac Markers | Troponin, CK-MB and BNP |
| Bone & Mineral Profile | Calcium, phosphate, magnesium, vitamin D |
| Hormones & Special Tests | Beta hCG, prolactin, fertility hormones, PSA and other markers |
Read each panel as a pattern, not a single number. And always compare with your previous reports — a trend across three reports tells a doctor far more than one result.
Key Biochemistry Reference Ranges
| Test | Typical Adult Range |
|---|---|
| Fasting Blood Sugar | 70 – 99 mg/dL |
| HbA1c | Below 5.7% (normal) · 5.7–6.4% prediabetes · 6.5%+ diabetes |
| ALT (SGPT) | 7 – 56 U/L |
| AST (SGOT) | 10 – 40 U/L |
| Bilirubin (Total) | 0.1 – 1.2 mg/dL |
| Creatinine | Men 0.7 – 1.3 mg/dL · Women 0.6 – 1.1 mg/dL |
| Blood Urea | 15 – 45 mg/dL |
| Total Cholesterol | Below 200 mg/dL (desirable) |
| LDL Cholesterol | Below 100 mg/dL (optimal) |
| Triglycerides | Below 150 mg/dL (desirable) |
| TSH | 0.4 – 4.5 mIU/L |
| Sodium / Potassium | 136 – 145 / 3.5 – 5.1 mmol/L |
| Calcium | 8.5 – 10.5 mg/dL |
| Vitamin D (25-OH) | 30 ng/mL or above (sufficient) |
Ranges vary slightly between laboratories and methods — always compare your result with the reference range printed on your own report.
How Biochemistry Testing Works
Conditions Biochemistry Helps Detect & Monitor
- Diabetes and prediabetes — glucose and HbA1c, the most searched tests on this site
- Liver disease — fatty liver, hepatitis, alcohol and medicine injury
- Kidney disease — creatinine and eGFR catch it while it is still silent
- Heart risk — the lipid profile guides prevention years before an event
- Thyroid disorders, vitamin D deficiency and gout — common, treatable, invisible without testing
Fasting Rules for Biochemistry Tests
- Fasting required (8–12 hours, water allowed): fasting blood sugar, lipid profile, fasting insulin
- Timed, not fasted: OGTT, 2-hour post-meal sugar, cortisol
- No fasting needed: HbA1c, LFT alone, kidney tests, thyroid profile, most hormones
Avoid alcohol for 24 hours before testing. It moves liver enzymes and triglycerides, and can distort an otherwise clean report.
Take your usual medicines unless your doctor says otherwise — and tell the lab what you took. If a result looks wildly different from your last one, ask about sample quality first: hemolysis alone can falsely raise potassium and AST.
Confused by a term on your report? The Report Decoder explains it in plain English. For weight-related risk, pair your results with our BMI Calculator.
Frequently Asked Questions
What does a biochemistry test show?
A biochemistry test measures chemicals, enzymes, and hormones in blood or urine to assess organ function, metabolism, and general health. It provides quantitative data about how well your body's systems are working and can detect abnormalities that indicate disease or dysfunction.
What is included in a liver function test (LFT)?
An LFT checks liver enzymes (SGPT/ALT, SGOT/AST), alkaline phosphatase (ALP), gamma-GT, bilirubin, and proteins (albumin and total protein) to evaluate liver health and detect diseases like hepatitis, fatty liver, cirrhosis, or bile duct obstruction.
What are kidney function tests (KFT) used for?
KFTs measure urea, creatinine, and electrolytes (sodium, potassium, chloride) to determine how efficiently your kidneys are filtering waste from the body. They help diagnose kidney disease, monitor chronic kidney conditions, and assess the impact of medications on kidney function.
What is the importance of thyroid profile testing?
A thyroid profile (T3, T4, TSH) helps diagnose conditions like hypothyroidism and hyperthyroidism, which affect metabolism, energy levels, weight, heart rate, and many other body functions. Regular thyroid testing is important for managing thyroid disorders and ensuring proper hormone balance.
Do biochemistry tests require fasting?
Some tests, such as lipid profile and fasting blood sugar, require 8–12 hours of fasting for accurate results. However, many other biochemistry tests can be performed without fasting. Always follow your doctor's specific instructions before testing to ensure reliable results.
What is HbA1c and why is it tested?
HbA1c measures the percentage of hemoglobin coated with sugar, giving your average blood glucose over the past 2–3 months. It is used to diagnose diabetes and prediabetes and to monitor how well treatment is working — and unlike fasting glucose, it needs no fasting.