C-peptide (Fasting) Test: Booking, Price, and Results
About C-peptide (Fasting) Test: Booking, Price, and Results
| Field | Value |
|---|---|
| Also Known As | Connecting peptide insulin, Insulin C-peptide, Proinsulin C-peptide, fCP |
| Sample Type | Venous blood (serum or plasma) |
| Fasting Required | Yes, 8 to 12 hours overnight fasting required |
| Report Time | 1 to 5 days |
| Recommended For | Adults and children of both genders; particularly those with diabetes or suspected low blood sugar |
| Price | Starting at ₹1,050 |
What Is a C-Peptide (Fasting) Test?
The C-peptide (fasting) test measures the level of C-peptide, a small protein fragment released by the pancreas alongside insulin. It tells doctors how much insulin your body is producing on its own. The test is commonly ordered for people with diabetes or unexplained episodes of low blood sugar. A small blood sample drawn from a vein in your arm is all that is needed.
What Does a C-Peptide (Fasting) Test Measure?
The C-peptide (fasting) test looks at a single key marker. The table below explains what it reflects and why it matters.
| Parameter | What It Reflects |
|---|---|
| Fasting C-peptide | The amount of insulin your pancreas is producing naturally, measured after an overnight fast |
C-peptide is released in equal amounts to insulin when the pancreas processes the precursor molecule proinsulin. As C-peptide stays in the bloodstream longer than insulin and is not affected by injected insulin medicines, it gives a reliable picture of your pancreas's own insulin output.
Why Is a C-Peptide (Fasting) Test Done?
A doctor may order this test for several reasons, from investigating diabetes type to looking for rare pancreatic conditions.
Common Symptoms That May Require This Test
The following symptoms are common reasons a doctor may request a C-peptide (fasting) test:
- Frequent urination and excessive thirst
- Unexplained weight loss
- Recurrent episodes of low blood sugar (hypoglycaemia) without a clear cause
- Symptoms suggesting insulin resistance, such as fatigue and weight gain around the abdomen
- General screening in known diabetes patients when treatment response is unclear
Conditions This Test Can Help Detect
This test can provide useful information in relation to several conditions:
- Distinguishing between Type 1 and Type 2 diabetes
- Insulinoma, a pancreatic tumour that produces excess insulin, leading to low blood glucose
- Cushing's syndrome, where the body produces too much of the hormone cortisol
- Addison's disease, where the adrenal glands do not produce sufficient hormones
- Liver disease and kidney failure
- Factitious hypoglycaemia, a condition where a person administers insulin to themselves secretly
C-Peptide (Fasting) Test for Chronic Disease Monitoring
- For people with latent autoimmune diabetes in adults (LADA), checking C-peptide levels at least every six months can help track how well the insulin-producing cells of the pancreas are still functioning.
- In Type 1 diabetes, monitoring C-peptide early in the disease helps doctors understand changes in blood sugar control.
- For patients with Type 1 and Type 2 diabetes, the test can guide treatment decisions, even for those already taking insulin.
How to Prepare and What to Expect
Getting ready for this test is straightforward. The steps below cover what you need to do before and during sample collection.
Do You Need to Fast?
Yes, fasting is required. You should avoid food and all beverages except water for 8 to 12 hours before the test. Plain water is permitted throughout the fasting period.
Practical Tips Before Your Test
Keep the following in mind before your appointment:
- Drink enough water during the fasting period to stay hydrated.
- Tell your doctor about all medicines, supplements, and herbal remedies you are taking.
- If you take biotin (vitamin B7), stop taking it at least 72 hours before the test, as it can interfere with results.
- Avoid strenuous physical activity on the day of the test.
Step-by-Step Procedure
Here is what typically happens on the day of your sample collection:
- A trained phlebotomist will ask you to sit comfortably and locate a vein, usually in the crook of your arm.
- A thin needle is inserted gently into the vein. You may feel a brief, mild sting.
- A small amount of blood is drawn into a collection tube. The whole process takes under two minutes.
- The needle is removed, and a small cotton pad is placed over the site. No stitches or dressing are needed.
- The sealed sample is labelled and sent to the laboratory for testing under appropriate storage conditions.
Factors That Can Affect Accuracy
Several factors may influence how reliable your results are:
- Whether the sample was collected in a true fasting state
- Kidney disease, particularly end-stage renal disease, which can raise C-peptide levels independently of insulin production
- Certain oral diabetes medicines, such as sulfonylureas, which stimulate insulin release
- The presence of anti-insulin antibodies, which can cause a falsely high reading
- Obesity and insulin resistance, which can elevate C-peptide even without a pancreatic disorder
Understanding Your C-Peptide (Fasting) Test Results
Your doctor will review your results alongside your blood glucose level, medical history, and overall health. The table below shows commonly used reference ranges.
| Parameter | Normal Range |
|---|---|
| Fasting C-peptide | 0.5 to 2.0 ng/mL (or 0.3 to 0.6 nmol/L) |
These ranges are general guidelines. Your doctor will interpret your results based on your age, health history, and other factors. Always consult a qualified healthcare professional for personalised medical advice.
Reference ranges can vary slightly between laboratories, so always refer to the ranges printed on your own report.
Results During Special Conditions
Kidney disease can significantly affect C-peptide (Fasting) test results. When kidney function declines, the body clears C-peptide more slowly, causing it to build up in the blood. Levels may be two to five times higher than in a person with normal kidney function, even if the pancreas is not actually producing more insulin.
In obese or insulin-resistant patients, C-peptide may appear normal or elevated even when autoimmune Type 1 diabetes is present, which can complicate interpretation.
How to Maintain Healthy Levels
These general wellness habits support balanced insulin function:
- Maintain a healthy body weight to help reduce insulin resistance.
- Follow a diet that is low in refined sugars and processed foods.
- Stay physically active in ways that your doctor considers appropriate for your health condition.
Lupin Diagnostics C-peptide (Fasting) Test Price and Home Collection
The C-peptide (Fasting) test is available at Lupin Diagnostics from ₹523, with home sample collection available across major Indian cities.
| City | Approximate Price (₹) |
|---|---|
| Mumbai | ₹1,100 |
| Bangalore | ₹1,100 |
| Hyderabad | ₹1,100 |
| Chennai | ₹1,050 |
| Kolkata | ₹1,100 |
| Pune | ₹1,100 |
How to Book
- Select the test on the Lupin Diagnostics website.
- Choose your city and preferred time slot.
- Opt for home sample collection by a certified phlebotomist, or visit your nearest Lupin Diagnostics centre.
- Receive your report via email or WhatsApp within the stipulated turnaround time.
Home Collection
Lupin Diagnostics offers home collection for the C-peptide (fasting) test across cities in India, so you can skip the travel and get tested from the comfort of your home. All samples are processed...
Frequently Asked Questions
C-peptide stays in the bloodstream for longer than insulin, with a half-life of around 20 to 30 minutes compared to just 3 to 5 minutes for insulin. This makes the C-peptide (fasting) test a more stable and reliable way to measure how much insulin your body is producing on its own. Unlike an insulin test, it is not affected by injected insulin medicines.
Yes, plain water is allowed during the fasting period. You should avoid all food, tea, coffee, and other drinks for 8 to 12 hours before the test.
No, this test does not diagnose diabetes on its own. Tests such as fasting blood glucose or HbA1c are used for that purpose. The C-peptide (fasting) test helps classify the type of diabetes and guide treatment decisions once a diagnosis has been made.
A fasting C-peptide level below 0.2 nmol/L is associated with Type 1 diabetes, indicating that the pancreas is producing very little or no insulin. Your doctor will review this result alongside other tests before drawing any conclusions.
When a patient has unexplained low blood sugar, the test helps distinguish between naturally high insulin production and self-administered insulin. People with an insulinoma have high levels of both C-peptide and insulin, whereas those who have injected insulin secretly will have high insulin but low C-peptide.
For patients with latent autoimmune diabetes in adults (LADA) who have C-peptide levels between 0.30 and 0.70 nmol/L, checking levels every 6 months may be useful for monitoring beta-cell function. The frequency for other diabetes patients depends on their condition and their doctor's guidance.
C-peptide (Fasting) Test: Booking, Price, and Results
