Serum Creatinine Test: Means, Normal Range, Price, Procedure

The serum creatinine test is a vital diagnostic test that measures the amount of creatinine in the blood. The level of creatinine in the body helps the healthcare provider to know the health status of the patient’s kidneys. An elevated quantity of creatinine in the body may indicate the presence of kidney-related disorders. 

Creatinine is a breakdown or waste product of creatine, a body substance that helps muscle generate energy for body activities such as intense exercise and heavy weightlifting.

Most times, the serum creatinine test is done with other medical tests, such as Blood Urea Nitrogen (BUN), Comprehensive Metabolic Panel (CMP), or Basic Metabolic Panel (BMP).

Serum creatinine tests can be performed for a variety of reasons. A healthcare provider may advise the patient to undergo a serum creatinine test to check: 

1. The stage of kidney disease.
2. How well a patient’s body reacts to a given kidney treatment.
3. The possible side effects of certain drugs, such as gentamicin (Garamycin, Gentasol).
4. How successful a kidney transplant has been.
5. The kidney health in patients with diabetes and high blood pressure.

The normal range for serum creatinine levels can vary from person to person slightly, depending on age, sex, and other factors. However, below is an average serum creatinine range that people should have:

1. Serum Creatinine Test Normal Range in Females: 0.59 to 1.04 mg/dL (52.2 to 91.9 micromoles/L)
2. Serum Creatinine Test Normal Range in Males: 0.74 to 1.35 mg/dL (65.4 to 119.3 micromoles/L)

If your serum creatinine levels are higher than the normal range, it may indicate that your kidneys are not functioning correctly. Depending on the severity of the elevation and other factors, your doctor may recommend further testing or refer you to a specialist for evaluation and treatment. 

Conversely, suppose your serum creatinine levels are lower than the normal range. In that case, it may indicate that your muscle mass is lower than expected, which can be a sign of malnutrition or other conditions.

A serum creatinine test does not only define serum creatinine levels in the body. But it also determines other factors, such as GFR, Albumin/creatinine ratio, and creatinine clearance. Let’s understand them in detail.

1. Glomerular Filtration Rate (GFR):
   1. Glomerulus are small filters found in kidneys that help eliminate waste from the blood. 
   2. The Glomerular Filtration Rate (GFR) helps detect the amount of blood passing through glomeruli per minute. 
   3. Normal range for GFR: 90 to 120 mL/min/1.73 m2.
   4. A GFR of less than 60 indicates kidney disorders/diseases.
2. Albumin/Creatinine Ratio:
   1. Albumin is a protein in the blood that helps prohibit fluid from leaking into other tissues. 
   2. A slightly elevated albumin/ creatinine ratio can indicate early kidney disease. In contrast, a high albumin/ creatinine ratio (ACR) raises the probability of diabetic nephropathy, also referred to as diabetic kidney disease.
   3. Normal albumin/creatinine ratio for men: less than 17mg/g
   4. Normal albumin/creatinine ratio for women: less than 25 mg/g
3. Creatinine Clearance:
   1. The removal of creatinine from the body is termed creatinine clearance. 
   2. Low creatinine clearance signifies kidney diseases and poor kidney function.
   3. Normal creatinine clearance for men (age 19 to 75):  77 to 160 mL/min/BSA.
   4. Normal creatinine clearance in women differs according to age group: 
      1. 18 to 29 years: 78 to 161 mL/min/BSA
      2. 30 to 39 years: 72 to 154 mL/min/BSA
      3. 40 to 49 years: 67 to 146 mL/min/BSA
      4. 50 to 59 years: 62 to 139 mL/min/BSA
      5. 60 to 72 years: 56 to 131 mL/min/BSA

Serum creatinine test results could be affected by various factors, like salt intake and creatinine supplements. Let’s learn about them in a more detailed manner.

1. Salt intake: Sodium and phosphate are linked with increased renal disorders. Hence, salt intake leads to affected serum creatinine results. 
2. Certain medications: Medicines can also cause a rise in serum creatinine. Therefore, it’s always best to talk to the doctor before taking medicines.
3. Protein: Protein contains creatine. When a person eats more protein than needed, the serum creatinine increases. 
4. Meat: Heat from cooked meat can turn creatine in meat into creatinine. Thus increasing serum creatinine. 
5. Creatine supplements: Creatine is a natural product made in the body. Hence, it’s best to avoid creatine through supplements. Otherwise, it can affect creatinine test results.

The serum creatinine test usually takes 5 minutes or less. A lab technician or a nurse performs this test on an outpatient basis in a clinic. Here’s a complete serum creatinine test procedure:

1. Firstly, healthcare staff will ask the patient to roll up their shirt/dress’s sleeve.
2. They tie a band above the elbow to help them find the vein easily. 
3. They will inject a sterile syringe into the patient’s vein and collect the blood sample.
4. A sterile cotton bud is then held on to the injected area, or they may apply a bandage. 
5. The blood sample is then sent to the pathology laboratory for examination. Depending on the laboratory, the patient receives the test report after a day or so.

A serum creatinine test is a low-risk diagnostic procedure. However, patients must do the preparations given below before and after a serum creatinine test to ensure they receive accurate results. 

Before Serum Creatinine Test

Before a serum creatinine test, your healthcare provider will likely provide you with instructions on how to prepare for the test.

1. Avoid eating or drinking for at least 8 hours or overnight. However, fasting depends on the patient’s health status. Hence, it’s best to consult the doctor.
2. Avoid supplements and medicines that could increase creatinine levels.
3. Avoid strenuous exercise or activity for 24 hours before the test.
4. Do not eat meat for a specific time. 
5. Moreover, everyone’s body is different. Therefore, patients are advised to talk to their healthcare providers about the complete serum creatinine test preparations. 

After Serum Creatinine Test

After a serum creatinine test, the healthcare provider will diagnose the disease depending upon the results of the serum creatinine test. Along with the serum creatinine test, the doctor may order several other tests to come to the correct diagnosis. 

The doctor may also conduct another test if the diagnosis is unclear or there’s a need for it. As the diagnosis is made, the doctor will plan the treatment accordingly. Depending on your results, your doctor may adjust your treatment plan or recommend lifestyle changes to help protect your kidney health. 

It's important to follow your doctor's recommendations and actively manage your kidney health, as early detection and intervention can help prevent or delay the progression of kidney disease.

The serum creatinine test is safe and bears no side effects. However, people may face a few risks, such as: 

1. Faintness and headaches on witnessing blood.
2. Redness in the injected area.
3. Pain from the injection.
4. Infection (e.g. infection caused by microorganisms present on injection).
5. Fatigue/ dizziness/ tiredness.
6. Fear (generally, Trypanophobia: fear of injection)

In India, the serum creatinine test cost in India ranges from ₹ 200 to ₹ 1500. However, the price may vary depending on several factors, including

1. Location: The cost of medical tests can vary depending on the city or region where the test is performed. Tests in larger cities may be more expensive than those in smaller towns or rural areas.
2. Type of laboratory: The serum creatinine test cost can vary depending on your laboratory type. Private laboratories may charge more than government-run laboratories but offer faster results and more specialised testing options.
3. Type of test: The serum creatinine test price can also vary depending on the type of test performed. Basic tests that only measure creatinine levels may be less expensive than more comprehensive tests that measure other kidney function indicators.
4. Additional tests: Depending on your medical condition, your doctor may recommend additional tests along with the serum creatinine test, which can increase the overall cost of testing.
5. Health insurance: If you have health insurance, the serum creatinine test cost may be covered partially or fully by your insurance provider.

A serum creatinine test is used to check the creatinine levels in the body. Healthcare providers generally conduct this test to examine the health status of a patient's kidneys. Although there’s no special preparation for the serum creatinine test, patients might have to fast for eight hours and avoid meat and certain supplements before the test. The best part about the serum creatinine test is that it bares no significant side effects. Moreover, the serum creatinine test is cost-effective and is priced between ₹ 200 to ₹ 1500.