Biomarker Glossary

Creatinine

Creatinine is a waste product made by your muscles and filtered out by your kidneys. A creatinine blood test, combined with the calculated estimated glomerular filtration rate (eGFR), is the standard UK test for assessing kidney function and screening for chronic kidney disease.

Also known as: Serum Creatinine

Creatinine is most informative when read alongside related markers like Albumin and Haemoglobin. A single number rarely tells the whole story. If your reading sits outside the typical range, share the full report with your GP or healthcare professional before drawing conclusions.

What is Creatinine?

Creatinine is produced at a steady rate by muscle as it uses creatine for energy. Healthy kidneys filter creatinine from the blood and pass it into urine. If kidney function falls, creatinine accumulates in the blood.

Creatinine alone is interpreted alongside eGFR (estimated glomerular filtration rate), a calculated marker of kidney filtration capacity. eGFR uses your creatinine value adjusted for age, sex and ethnicity.

Creatinine is not a perfect marker. Muscle mass, age, ethnicity, recent strenuous exercise, hydration and some medications all influence the result. Trends over time are usually more informative than a single reading.

Why test Creatinine?

  • To screen for chronic kidney disease, particularly in people with diabetes, high blood pressure or family history of kidney disease.
  • To monitor known kidney disease.
  • Before starting medications that affect the kidneys (some painkillers, blood pressure drugs, contrast dye).
  • To assess kidney function during pregnancy planning.
  • As part of any general health, metabolic or biohacking panel.
To screen for chronic kidney disease, particularly in people with diabetes, high blood pressure or family history of kidney disease.

Creatinine normal range (UK)

Result What it means
Men: 60 to 110 micromol/L Normal
Women: 45 to 90 micromol/L Normal
eGFR above 90 mL/min/1.73m² Normal kidney function
eGFR 60 to 89 Mildly reduced (Stage 2 CKD if persistent and accompanied by other signs)
eGFR 45 to 59 Moderately reduced (Stage 3a CKD)
eGFR 30 to 44 Moderately reduced (Stage 3b CKD)
eGFR below 30 Severely reduced (Stage 4 to 5 CKD, often requires specialist care)

Reference ranges are based on UK Kidney Association guidance. Single readings can be misleading. CKD requires persistently abnormal results (typically over 3 months) plus signs of kidney damage.

About these ranges. The ranges above are typical UK clinical lab ranges aligned to NHS and Royal College of Pathologists guidance. Your Chxhealth report will show the specific reference range used by our partner lab, Randox, for each marker. Lab ranges vary slightly between providers and assays. Always interpret your results in the context of the range printed on your own report.

What causes high Creatinine?

  • Acute kidney injury (dehydration, infection, medication effects)
  • Chronic kidney disease (diabetes, high blood pressure are leading UK causes)
  • Heart failure
  • Urinary tract obstruction (stones, prostate enlargement)
  • High muscle mass (creatinine reflects muscle bulk)
  • Recent strenuous exercise
  • High protein diet or creatine supplementation
  • Some medications: NSAIDs, ACE inhibitors, certain antibiotics

What causes low Creatinine?

  • Low muscle mass (older adults, sedentary lifestyle, prolonged illness)
  • Pregnancy (kidney filtration increases)
  • Severe liver disease (reduced creatinine production)
  • Some medications

Symptoms of high Creatinine

  • Often no symptoms in early kidney disease.
  • Fatigue, weakness
  • Swelling of feet and ankles
  • Reduced urine output
  • Blood in urine, foamy urine
  • Itching, particularly in advanced kidney disease
  • Nausea, loss of appetite
  • High blood pressure

Symptoms of low Creatinine

  • Usually reflects low muscle mass and is not symptomatic by itself.

How is Creatinine tested?

Creatinine is measured from a small blood sample. No fasting is required.

Avoid strenuous exercise for 24 hours before the test, as it transiently raises creatinine.

Avoid creatine supplements for 48 hours before testing.

eGFR is automatically calculated from your creatinine, age and sex.

Chxhealth samples are analysed by Randox, a UK laboratory accredited by UKAS. Results return in 3 to 5 working days.

How to support healthy Creatinine levels

  • Control blood pressure. High blood pressure is the leading cause of kidney damage in the UK.
  • Control blood sugar if you have diabetes or prediabetes.
  • Stay well hydrated.
  • Limit excess protein and creatine supplementation if you have known kidney issues. For people with healthy kidneys, normal protein and creatine intake is fine.
  • Avoid long term high dose NSAIDs (ibuprofen, naproxen) without medical guidance.
  • Do not smoke. Smoking accelerates kidney damage in CKD.

These are general lifestyle suggestions. Chxhealth is an information service. For personal medical advice, please speak to a healthcare professional.

Chxhealth panels that test Creatinine

10 Chxhealth biomarker panels include Creatinine. Each is analysed by Randox, a UK laboratory accredited by UKAS. Reports are delivered in 3 to 5 working days.

Creatinine FAQs

What is a normal creatinine level?

60 to 110 micromol/L for men and 45 to 90 micromol/L for women is the standard UK range. Athletic adults with high muscle mass often run slightly higher, while older or smaller adults may run lower.

What does eGFR mean?

Estimated Glomerular Filtration Rate. It tells you how well your kidneys are filtering, in mL per minute. Above 90 is normal. Below 60 (if persistent for 3 months) is the definition of chronic kidney disease.

Can muscle mass affect creatinine?

Yes, significantly. A muscular adult may have a creatinine of 110 to 130 with completely normal kidney function. This is why eGFR (which adjusts for age and sex) is used alongside raw creatinine.

Does creatine supplementation affect the test?

Yes. Creatine supplements typically raise blood creatinine by 10 to 30 percent without any change in actual kidney function. Stop creatine for at least 48 hours before testing.

Can kidney function recover?

Acute kidney injury often recovers fully when the cause is treated. Chronic kidney disease can be slowed and stabilised with good blood pressure control, diabetes management and lifestyle changes, although established damage is rarely fully reversed.

Often tested with Creatinine

The biomarkers below are commonly investigated alongside Creatinine because they reveal connected aspects of the same physiological picture:

  • Albumin: Renal and synthetic markers reported together.
  • Haemoglobin: Chronic kidney disease often causes anaemia.
  • ALT: Multi-organ pictures benefit from liver markers alongside renal.

Choose the right test for your goal

If you are reading about Creatinine because of a specific health goal, our buying guides walk you through which Chxhealth panels fit:

Sources and further reading

This page is informed by guidance from the NHS, NICE, Royal College of Pathologists and other UK authoritative bodies. For deeper detail or to verify the information, see:

About this page. Last reviewed: 13 May 2026. Next scheduled review: May 2027. This page has not yet been independently reviewed by a clinician. It is written from authoritative UK medical guidance (NHS, NICE, Royal College of Pathologists, peer-reviewed sources) but has not undergone formal clinical sign off.

Important. Chxhealth is a UK information service. We do not diagnose, treat or prescribe. The reference ranges and information on this page are general educational content and should not be used as a substitute for advice from a qualified healthcare professional. For any concerns about your health or results, please speak to your GP or another healthcare professional.