It is a measure of kidney function. It can be calculated based on serum creatinine.

There are 5 stages of CKD based on eGFR. Stage 5 is when eGFR is < 15 ml/min

Yes. Pain killers (NSAIDs), certain antibiotics, and other drugs can cause kidney problems. One should discuss a nephrologist and avoid over the counter medicines.

eGFR, based on serum creatinine and urine albumin to creatinine ratio are tests to rule out kidney disease. Ultrasound scan can be added to above tests.

For high risk groups, eGFR should be done annually. If there is established kidney disease, it may be required more frequently depending upon the stage of CKD.

No. Acute kidney injury / failure are mostly treatable and reversible.

One should keep blood glucose, blood pressure under control. Avoid unnecessary medicines including herbal or ayurvedic. Drink adequate water.

Purification of blood and removal of toxins accumulated as a result of kidney failure is called dialysis.

Yes. Kidney Transplant is another better option.