GFR | Glomerular Filtration Rate Test

Glomerular filtration rate (GFR) test is a laboratory technique that is used to determine how functional your kidneys are, at removing the wastes and toxins from the blood. Specifically, it estimates how much blood passes through the glomeruli (the tiny filters in the kidneys) each minute (based on the excretion of certain known and measurable chemicals).Kidneys are bean shaped organs that are responsible for removing excess water, nitrogenous waste products, unneeded excessive salts/ electrolytes and end-products of different drugs and hormones (Hormonal Imbalances In Men) from the body. Needless to say that accumulation of these compounds in the body can lead to diseases, infections (Bladder Infection Causes | Catheter) and organic complications.

Significance of a GFR Test

Kidneys are remarkable; despite the small size (about 4-5 inches), the renal tissue is capable of filtering about 60-90ml of blood per minute. However, not all the ingredients are freely filtered/ excreted by the renal cells (Renal Cell Wiki Page). For example, depending upon your tissue hydration status, some water is reabsorbed by the terminal parts of kidney. Same is true for electrolytes and other agents. That’s why the principle of this test is based on the excretion of creatinine.Creatinine, a by-product of wear and tear of muscles, is freely filtered by the kidneys and none of it is reabsorbed. Hence, measurement of its amount determines the efficiency of the kidneys. If your kidneys are compromised, Creatinine levels will be altered that may suggest a possible renal issue.

Conditions in Which a GRF Test is Performed

Although, GFR (or the rate at which human kidneys filter the blood) decreases with physiological aging, certain health issues and risk factors can significantly alter the renal capacity prematurely. A few of these are:

• Certain immunological diseases (like systemic lupus erythematous)

• Intake of some toxins, chemicals and drugs (like alcohol, ethylene glycol, almost all pharmacological agents especially acetaminophen, hormonal agents)

• Uncontrolled metabolic disorders and resulting complications (like uncontrolled diabetes (Diabetes and Erectile Dysfunction), hypertension)

• Recurrent attacks of UTI (UTI Antibiotics | Urinary Tract Infections)(urinary tract infection)

• Family history (or genetic conditions) affecting kidney.

However, with the help of this test, healthcare providers can determine if medical/ pharmacological interventions are needed to safeguard renal function.

Renal Health & GFR Status

Kidney function is classified into 5 stages based on GFR. The normal Creatinine clearance is 100%. Stage 1 and 2 are suggestive of normal renal function or mild disease; however, with deteriorating renal function, the chances of complications increases significantly.

Stage 1: GFR is 90 mL/min/1.73 m2 or more.Stage 2: GFR is 60-89 mL/min (mild renal dysfunction)Stage 3: GFR is 30-59 mL/min (moderate renal dysfunction)Stage 4: GFR is 15-29 mL/min (severe renal dysfunction and impending renal failure)Stage 5: GFR is less than 15 mL/min (suggestive of renal failure that require urgent and emergent medical attention)

Limitations of a GFR Test

The Creatinine (Creatinine Wiki Page) levels and metabolism is different in following individuals and therefore the test may not represent renal function adequately:Conditions in which creatinine production is high and may give a false impression of satisfactory renal function in the presence of a possible issue:

• Body builders

• Athletes

• Patient with acute kidney failure

Likewise, there are certain conditions in which creatinine production is low and may give a false impression of renal disease when renal function is satisfactory.

• Patients with muscle wasting conditions.

• Patients with amputated arm or leg (these individuals have lower creatinine clearance due to low muscle mass)

• Malnourished individuals.

• Pregnancy

• Patients with edema.

Improve Your GFR

GFR can be increased by improving the blood flow to the kidneys without altering the circulatory pressure. When blood vessels are dilated (widened), blood flow in kidneys can be increased that can directly improve GFR. This can be accomplished by increasing your water intake and by incorporating regular physical activity (Workout Time Learn More) in your lifestyle.Following steps can help improve GFR and kidney function. Consult with your physician to avoid any confusion and mishaps.

• GFR | Glomerular Filtration Rate Test Fluid Intake: Unless you are on dialysis or your doctor has restricted fluid intake for other reasons, increase your water intake to at least 2.5 liters per day. Make sure to consume clear water and avoid alcoholic (Alcohol Binge Drinking) beverages to minimize the damage to renal tubules

• Reduce sodium and other salts intake: Replace sodium and salt intake with spices and condiments since sodium is known to cause edema (fluid retention) thereby increasing the pressure on renal tubules.

• Consume fresh meat that is low in sodium content. Sodium also increases the blood pressure (Blood Pressure | ED) and leads to cardiovascular disorders

• Low fat diet with high good cholesterol content: Reduce oily and sticky substances. Consume a low fat dairy-free diet (if you are on dialysis avoid dairy as It contains phosphorus).

• Green vegetables and fresh fruits: Consume meals rich in vegetable (Fruit And Veg) and grains. Antioxidants (Superfood Alternatives) present in these foods help in neutralizing chemicals and toxins from the blood. Likewise, reduce the intake of preservatives and toxins that may alter your renal function.

• Consume low protein diet: check with your healthcare provider to determine the amount of protein you should consume to maintain normal kidney function.

References:

Levey, A. S., Atkins, R., Coresh, J., Cohen, E. P., Collins, A. J., Eckardt, K. U., ... & Eknoyan, G. (2007). Chronic kidney disease as a global public health problem: approaches and initiatives–a position statement from Kidney Disease Improving Global Outcomes. Kidney international, 72(3), 247-259.Sowers, J. R., & Epstein, M. (1995). Diabetes Mellitus and Associated Hypertension, Vascular Disease, and Nephropathy An Update. Hypertension, 26(6), 869-879.