Cystatin - C Test

Chronic Kidney Disease and other renal disorders

The Cystatin C test measures the amount of cystatin C in your blood.

Your body produces Cystatin C constantly, and it is found in various body fluids, including blood, spinal fluid, etc. When your kidneys are in a healthy state, they filter cystatin C out of the blood through urine.

Cystatin C test is used to assess the functioning of your kidneys or renal system. The levels of protein measure glomerular filtration rate (GFR). Levels of GFR show how well the kidneys are working. Doctors may also use it to evaluate the progression of a particular kidney disease that a patient might have.

When your doctor suspects a kidney-related disease, he might prescribe a Cystatin C test. This is because, in most cases, the levels of creatinine serum are not reliable. Creatinine serum determines the amount of creatinine in your blood.

The concentrations of cystatin C in the blood are normal when the renal system functioning is normal. However, as kidney function deteriorates, the level begins to rise. This increase in cystatin C occurs as the glomerular filtration rate falls.

Cystatin C levels change with a change in glomerular filtration rate, which is why it is a reliable indicator for the evaluation of renal disorders.

Some symptoms might prompt your doctor to recommend a Cystatin C test. These include:

• Change in the amount of urine passed in a day
• Water retention in different body parts
• Dyspnoea or shortness of breath
• Painful sensation in the chest
• Seizures

The prevalence of kidney disease in India is around 800 per million of the population.

What Does the Cystatin C Test Measure? and Who is It Prescribed For?

Cystatin C test measures the amount of cystatin C in the blood, which is useful in evaluating the functioning power of kidneys in the body.

A doctor generally advises a Cystatin C test in people who are at higher risk of kidney dysfunction:

• People who have diabetes or high blood pressure.
• People who have a family history of kidney-related problems.
• People who fall under the obese category.
• People who have had acute kidney injury.
• People who are regular smokers.

Doctors prescribe Cystatin C if a patient at high risk shows the following symptoms:

• Stomach troubles or acute pain in the stomach.
• Nausea
• Fatigue
• Excessive dry and itchy skin.
• Foamy urine or blood in the urine.

Much like other tests and diseases, early detection is advisable, and a doctor’s advice is paramount.

How do you reduce Cystatin C?

The most effective ways to lower Cystatin C levels are as follows:

• Regular exercise
• A healthy but low-protein diet that improves kidney function
• Quit smoking
• Control blood sugar
• Maintain normal blood pressure

What does it mean when Cystatin C is high?

High levels of Cystatin C indicate kidney dysfunction. This means the GFR is low, and the kidney is not filtering the bodily fluids effectively. There are some conditions in which there could be a slight increase in Cystatin C:

• Smoking
• Alcohol
• Obesity
• Ageing
• Genetics
• Chronic inflammation
•  Hyperthyroidism
•  Physical inactivity
• Medical treatment includes corticosteroids,
• Pregnancy

What if Cystatin C is low?

Low levels of Cystatin C mean the levels are below the reference range. The following conditions can lead to lower Cystatin C levels:

•  Kawasaki disease
• Bladder cancer
• Genetics
• Hypothyroidism
•  Neuromyelitis Optica spectrum disorders

Low levels of Cystatin C can also be the indicator of the onset of the following conditions:

• Hardening of the arteries
• Aneurysms
• Alzheimer's disease

Any deviation from the normal range of the cystatin c test is a measure of kidney function and the glomerular filtration rate.

A cystatin C test can help your doctor find your GFR (glomerular filtration rate). Cystatin C is filtered out of the blood by the glomeruli, which are the groups of tiny blood vessels in the kidneys. The levels of cystatin C in the blood indicates the glomerular filtration rate (GFR)

GFR is the rate at which the renal fluid is filtered. A decline in kidney function causes GFR to go down and increases cystatin C and other proteins and elements, such as creatinine and urea, in the blood. The levels of these substances increase because the kidneys cannot properly filter the blood at a normal rate, leading to the accumulation of these substances in the blood.

Alternatively, an improvement in kidney function leads to increases in GFR, which causes levels of cystatin C, creatinine, and urea to decline due to the kidneys being able to remove them from the blood effectively.

High levels of Cystatin C are usually caused by underlying medical conditions such as kidney disorder, HIV, diabetes, high blood pressure or cancer.

While high Cystatin C is bad for kidneys, a low level of Cystatin C is equally harmful as it indicates a higher risk of Alzheimer’s and hardening of arteries. A Cystatin C is essential as it clearly reports the amount of Cystatin C level in your body and if any medication is required to bring it in the normal range.

This Cystatin C test requires blood as a sample.

Test Preparation

The cystatin c test is a blood test that does not require fasting or any specific preparation. The usual way to collect a blood sample is by drawing it from one of the veins. This is known as venipuncture. This vein is usually the most prominent one in the forearm of a person. This procedure lasts for five minutes.

Cystatin C Test Inclusions: What are the Parameters Included?

Cystatin C is a considerably small protein. It is produced throughout the body by all the cells that contain a nucleus. It is produced, filtered from the blood by the kidneys.

The Cystatin C test measures the levels of the protein in the blood.

The cystatin c test is applicable for males and females, both adults and children.

How Frequently Should You Take Cystatin C Test?

Cystatin C test should be taken whenever your healthcare provider suspects some sort of kidney dysfunction and your serum creatinine level measurements are not reliable.

This test may also be done at regular intervals for those patients who suffer from chronic kidney diseases.