Cystatin C Test | London Blood Tests UK

Assess kidney function accurately with our Cystatin C blood test for £88. UKAS-accredited testing, fast results, and optional GP consultation.

The Cystatin C Test is a highly sensitive blood test used to assess kidney function and early renal impairment, often detecting changes earlier than creatinine. Testing is performed in a UKAS-accredited laboratory, with results typically available within 10 business days and an optional GP consultation for interpretation.

What is a Cystatin C Blood Test?

Cystatin C is a small protein produced by all nucleated cells in the body at a constant rate. It is freely filtered by the kidneys and almost completely reabsorbed and broken down, making it a reliable marker of glomerular filtration rate (GFR).

Unlike creatinine, Cystatin C levels are less influenced by muscle mass, age, sex, or diet, making it particularly useful in individuals where creatinine may underestimate kidney dysfunction — such as older adults, athletes, people with low muscle mass, or those with chronic illness.

The Cystatin C Blood Test provides a more accurate assessment of kidney function and can be used alone or alongside creatinine to calculate a more precise estimated GFR (eGFR). It is widely used in nephrology for early detection of kidney disease and cardiovascular risk stratification.

At London Blood Tests, analysis is performed using validated immunoassay methods aligned with UK clinical standards.

Benefits of the Cystatin C Test

1. Early Detection of Kidney Dysfunction
   Identifies subtle reductions in kidney filtration earlier than creatinine-based tests.

2. More Accurate GFR Estimation
   Provides a reliable assessment of kidney function, especially when muscle mass affects creatinine accuracy.

3. Useful for High-Risk Individuals
   Particularly valuable for people with diabetes, hypertension, cardiovascular disease, or a family history of kidney disease.

4. Less Affected by Lifestyle Factors
   Unlike creatinine, Cystatin C is minimally influenced by diet, exercise, or body composition.

5. Supports Medication Safety
   Helps clinicians assess kidney function before prescribing or adjusting medications cleared by the kidneys.

6. Improves Cardiovascular Risk Assessment
   Elevated Cystatin C levels are associated with increased cardiovascular and mortality risk.

7. Optional GP Consultation for Interpretation
   Results can be reviewed with a GP to guide further testing, lifestyle changes, or specialist referral.

Why Do I Need a Cystatin C Blood Test?

You may benefit from a Cystatin C Test if you:

• Have diabetes or high blood pressure

• Have borderline or inconsistent creatinine results

• Are older than 60 years

• Have low muscle mass or are very physically active

• Have a family history of kidney disease

• Are monitoring known chronic kidney disease

• Require accurate kidney function assessment before medication use

Common symptoms that may prompt testing include:

• Fatigue or weakness

• Swelling in ankles or around the eyes

• Changes in urination frequency

• Foamy urine

• Unexplained high blood pressure

Because early kidney disease is often asymptomatic, Cystatin C testing plays a key role in preventive health screening.

How the Test Works

In-Clinic Testing at London Blood Tests

1. Book Your Appointment

   • Book online or by phone at your preferred clinic location.

   • No fasting is required.

2. Pre-Test Review

   • You may be asked about medications, kidney history, or recent illness.

3. Sample Collection

   • A trained phlebotomist collects a small venous blood sample.

   • The procedure takes 5–10 minutes.

4. Laboratory Analysis

   • Samples are sent to a UKAS-accredited laboratory.

   • Cystatin C is measured using validated immunoassay techniques.

5. Quality Control

   • Results undergo strict internal verification before release.

6. Results Delivery

   • Results are typically available within 10 business days via your secure portal.

7. Optional GP Consultation

   • Book a GP review to interpret your kidney function and discuss next steps.

At-Home Blood Draw (Home or Hotel Phlebotomy – UK-Wide)

1. Book Your Visit

   • Arrange a phlebotomist home or hotel visit at a time that suits you.

2. Professional Blood Collection

   • A certified phlebotomist visits your location and collects a venous blood sample.

3. Sample Transport

   • The sample is labelled and couriered the same day under controlled conditions.

4. Laboratory Testing

   • Analysis is identical to in-clinic testing.

5. Results & Follow-Up

   • Results delivered online within 10 business days, with optional GP review.

Your Cystatin C Test Results – Explained

Your report will include your Cystatin C concentration and may also provide a calculated eGFR (Cystatin C-based).

• Typical reference range: approximately 0.6–1.2 mg/L

• Lower values: generally indicate normal kidney filtration

• Higher values: suggest reduced kidney function or early renal impairment

Interpretation may include:

• Normal kidney function

• Mild reduction in GFR

• Moderate to severe kidney impairment

Cystatin C results are often interpreted alongside creatinine, urea, electrolytes, and urine markers for a complete renal assessment.