Kidney Function Test (KFT): Creatinine, eGFR, Urea and the Early Warning Signs

Quick answer: A Kidney Function Test (KFT) usually includes serum creatinine, the calculated eGFR, blood urea/BUN, uric acid and electrolytes (sodium, potassium, chloride). The single most important number is eGFR — an eGFR of 90 or above is normal, 60–89 may be mildly reduced, and below 60 for three months or more indicates chronic kidney disease. A urine albumin-to-creatinine ratio (ACR) detects early kidney damage before eGFR falls. People with diabetes, high blood pressure, obesity, or a family history of kidney disease should test at least once a year.

Kidney disease is called a silent disease because symptoms usually appear only when much of the kidney's function has already been lost. In India, diabetes and high blood pressure are the two leading causes. Gurugram's heat, dehydration, high-protein diets and widespread use of over-the-counter painkillers add further strain.

What Your Kidneys Do

• Filter waste and excess fluid from the blood
• Balance sodium, potassium and other electrolytes
• Control blood pressure
• Make a hormone (erythropoietin) that helps produce red blood cells
• Activate vitamin D for bone health

What a KFT Measures

Serum Creatinine

A waste product from muscles, filtered by the kidneys. When kidney function falls, creatinine rises. Normal ranges depend on muscle mass, age and sex — roughly 0.7–1.3 mg/dL in men and 0.6–1.1 mg/dL in women, though labs vary.

Creatinine can be raised by high muscle mass, creatine supplements, heavy exercise and a large meat meal, and can look "normal" in older or thin people even when function is reduced. That's why eGFR is more useful.

eGFR (Estimated Glomerular Filtration Rate)

Calculated from creatinine, age and sex, eGFR estimates how many millilitres of blood the kidneys filter each minute.

• 90 or above: normal (if no other signs of kidney damage)
• 60–89: mildly reduced — significant if there's also protein in urine
• 45–59 and 30–44: moderately reduced
• 15–29: severely reduced
• Below 15: kidney failure

A single low value can be due to dehydration or a recent illness; your doctor will usually repeat it.

Blood Urea / BUN

Also a waste product. It rises with kidney dysfunction, but also with dehydration, high-protein diets and gastrointestinal bleeding.

Uric Acid

High uric acid is linked to gout and kidney stones and may contribute to kidney damage. See uric acid and gout in young Indians.

Electrolytes — Sodium, Potassium, Chloride

Kidneys keep these in a narrow range. High potassium is particularly important because it can affect heart rhythm. Heat, vomiting, diarrhoea, diuretics and some BP medicines can disturb electrolytes.

Urine Albumin-to-Creatinine Ratio (ACR / Microalbumin)

Detects small amounts of protein leaking into urine — one of the earliest signs of kidney damage, especially in diabetes. An ACR below 30 mg/g is normal. Read our urine analysis guide.

Early Warning Signs of Kidney Problems

Most people have no symptoms early on. Later signs include:

• Swelling of feet, ankles or around the eyes
• Foamy or frothy urine (possible protein)
• Passing urine more often at night
• Tiredness and poor concentration
• Loss of appetite, nausea
• Itchy skin
• Muscle cramps
• High blood pressure that is hard to control

Who Should Get a Kidney Function Test?

• Everyone with diabetes — yearly KFT and urine ACR
• Everyone with high blood pressure
• People with obesity, heart disease or a family history of kidney disease
• Adults over 60
• People who regularly take painkillers (NSAIDs) like ibuprofen or diclofenac
• People with recurrent kidney stones or UTIs
• Those taking long-term medicines that need kidney monitoring
• Before surgery — see pre-operative tests

Heat, Dehydration and Your Kidneys

Gurugram's summers and long outdoor commutes increase the risk of dehydration, which temporarily raises urea and creatinine and, when severe or repeated, can injure the kidneys. Drink water steadily through the day, especially in heat, during illness with vomiting or diarrhoea, and after exercise.

How to Prepare for a KFT

• Fasting is usually not required for KFT alone; follow instructions if combined with other tests
• Avoid heavy exercise for 24–48 hours
• Avoid a large meat meal the night before
• Tell the lab about creatine supplements and medicines
• Stay normally hydrated

Protecting Your Kidneys

• Keep blood sugar and BP in target
• Avoid regular use of over-the-counter painkillers without medical advice
• Limit salt and processed food
• Stay hydrated
• Don't smoke
• Test regularly if you're at risk

Frequently Asked Questions

What is a normal eGFR?

An eGFR of 90 mL/min/1.73m² or above is normal. Values below 60 for three months or more indicate chronic kidney disease.

Is fasting needed for a kidney function test?

Fasting is generally not required for a KFT alone. If other tests like blood sugar or lipid profile are being done, fasting may be needed.

Can dehydration affect kidney test results?

Yes. Dehydration can temporarily raise urea and creatinine. Your doctor may repeat the test after you are well hydrated.

What is the earliest test for kidney damage in diabetes?

The urine albumin-to-creatinine ratio (microalbumin) detects early kidney damage in diabetes before creatinine or eGFR change.

Does creatine supplement affect creatinine?

Yes. Creatine supplements and high muscle mass can raise serum creatinine. Tell your doctor and the lab if you take creatine.

Which Aarvak packages include KFT?

The ₹2,000 ADC Mini Swasthya Panel and ₹3,000 ADC Swasthya Panel include a Kidney Function Test.

Book a Kidney Function Test in Gurugram

Kidney damage is far easier to slow when caught early. Book a KFT at our Sector 67 lab or at home, or choose the ₹2,000 ADC Mini Swasthya Panel, which includes KFT, LFT, thyroid, sugar and cholesterol. Call +91 92663 33711.

This article is for general information and does not replace medical advice.