What are other Names for this Test? (Equivalent Terms)
- Inulin Clearance Test for Kidney Damage
What is the Inulin Clearance Blood Test? (Background Information)
- Inulin is a sugar found in plants that is poorly digested by humans. It is used to estimate the health of the kidneys by assessing their ability to filter inulin from blood, after it has been administered
- The kidneys, along with the liver and spleen, filter blood and excrete the waste as urine. The site of filtration is a microscopic sieve-like structure called the glomerulus. There are roughly 1 million glomeruli in each kidney
- The Inulin Clearance Blood Test helps determine the inulin clearance rate, which is the rate at which inulin leaves blood. It helps assess kidney function
- The Inulin Clearance Blood Test is performed by administering a dose of inulin and measuring the rate at which it decreases in blood (as it is filtered out by the kidneys into the urine)
- The rate at which the glomeruli filter blood is called the glomerular filtration rate (GFR). The normal value for the Inulin Clearance Blood Test should be the same as that of the GFR
What are the Clinical Indications for performing the Inulin Clearance Blood Test?
Following are the clinical indications for performing the Inulin Clearance Blood Test:
- Evaluating kidney disease
- Screening diabetics for early signs of nephropathy
How is the Specimen Collected for Inulin Clearance Blood Test?
Following is the specimen collection process for Inulin Clearance Blood Test:
Sample required: Blood
Process of obtaining a blood sample in adults:
- A band is wrapped around the arm, 3-4 inches above the collection site (superficial vein that lies within the elbow pit)
- The site is cleaned with 70% alcohol in an outward spiral, away from the zone of needle insertion
- The needle cap is removed and is held in line with the vein, pulling the skin tight
- With a small and quick thrust, the vein is penetrated using the needle
- The required amount of blood sample is collected by pulling the plunger of the syringe out slowly
- The wrap band is removed, gauze is placed on the collection site, and the needle is removed
- The blood is immediately transferred into the blood container, which has the appropriate preservative/clot activator/anti-coagulant
- The syringe and the needle are disposed into the appropriate “sharp container” for safe and hygienic disposal
Preparation required: No special preparation is needed prior to the test.
What is the Significance of the Inulin Clearance Blood Test Result?
The interpretation of the Inulin Clearance Blood Test value depends on the age and gender of the individual. The range of value is given as follows:
- Children less than 11 years: 82-122 mL/min
- Children aged 11-20 years: 84-125 mL/min
- Men aged 21-39 years: 90-168 mL/min
- Women aged 21-39 years: 84-150 mL/min
- Men aged 40-49 years: 78-162 mL/min
- Women aged 40-49 years: 82-146 mL/min
A low value for the Inulin Clearance Blood Test may point to a diagnosis of the following conditions:
- Acute and chronic glomerulonephritis
- Acute tubular necrosis
- Advanced chronic bilateral pyelonephritis
- Renal atherosclerosis
- Congestive heart failure (CHF)
- Renal malignancy
- Polycystic kidney disease
The laboratory test results are NOT to be interpreted as results of a "stand-alone" test. The test results have to be interpreted after correlating with suitable clinical findings and additional supplemental tests/information. Your healthcare providers will explain the meaning of your tests results, based on the overall clinical scenario.
Additional and Relevant Useful Information:
- The Inulin Clearance Blood Test is considered the most reliable measure of kidney filtration ability. However, it is difficult to perform the test, and thus, it is rarely used
Certain medications that you may be currently taking may influence the outcome of the test. Hence, it is important to inform your healthcare provider, the complete list of medications (including any herbal supplements) you are currently taking. This will help the healthcare provider interpret your test results more accurately and avoid unnecessary chances of a misdiagnosis.
The following DoveMed website links are useful resources for additional information:
Please visit our Laboratory Procedures Center for more physician-approved health information: