Summarize this article in one sentence.
During later stages of kidney disease, your doctor may recommend you to specialist capable of devising the best diet for your condition. These specialists are known as "renal dieticians."  Your renal dietician will work with you to reduce the stress on your kidneys while maintaining a balance between the fluids and minerals in your body. Most specialized diets will include elements similar to those described in this article. For instance, you might be instructed to reduce your intake of sodium, potassium, phosphorus, and protein. Most CKD and low GFR rates are caused or influenced by other underlying conditions. In such cases, you'll need to get these other ailments under control before you can raise your GFR.  High blood pressure and diabetes are the two most common causes. When the cause of kidney disease isn't easily identifiable, your doctor may administer additional tests to diagnose the issue. These may include urine tests, ultrasounds, and CT scans. In some cases, your doctor may recommend a biopsy to remove and evaluate a small sample of kidney tissue. When another condition causes kidney disease, or when kidney disease causes related problems, your doctor may prescribe certain medications to help treat your overall condition.  High blood pressure is often linked to low GFR, so you may need some type of blood pressure medication. Options include angiotensin-converting enzyme inhibitors (captopril, enalapril, and others) or angiotensin receptor blockers (losartan, valsartan, and others). These drugs can maintain blood pressure while also reducing protein levels in your urine, allowing your kidneys to work less hard as a result. During late stages of kidney disease, your kidneys may not be able to produce an important hormone called "erythropoietin," so your doctor may need to prescribe drugs that can help remedy the problem. You may also need vitamin D supplements or other drugs to help control phosphorus levels since your kidneys will have difficulty filtering phosphorus in the body. All drugs are filtered through the kidneys, so you should discuss any medication you plan to use with your doctor while your GFR levels are low. This includes both prescription and non-prescription drugs.  You may need to completely avoid NSAID and COX-II inhibitor drugs. Common NSAID drugs include ibuprofen and naproxen. One common COX-II inhibitor is celecoxib. Both drug classes have been linked to increased incidents of kidney disease. Talk with your doctor before trying any herbal remedy or alternative treatment, as well. "Natural" treatments are not necessarily better for you, and if you aren't careful, you could take something that may make your GFR levels dip lower. Even if you successfully increase your GFR, you should continue to check your GFR throughout your lifetime. This is especially true if you've ever had lower than average rates or if you face an elevated risk of kidney disease. GFR and kidney function naturally decline with age, so your doctor will likely recommend continued exams to help monitor the rate of decline. He or she may need to adjust your medications or dietary recommendations based on any changes to your GFR. If your GFR is extremely low and you've entered into renal failure, you'll need to go on dialysis to filter waste products and excess fluid from your system.  Hemodialysis involves the use of an artificial kidney machine with a mechanical filter. Peritoneal dialysis uses the lining of the abdomen to help filter and clean waste products from your blood. Kidney transplants are another option for people with advanced kidney disease and exceptionally low GFR. You'll need to be matched with the right donor before a transplant can take place. Oftentimes the donor is a relative, but in many cases, it may also be a stranger.  Not everyone with advanced kidney disease qualifies as a candidate for transplant, however. Age and medical history may rule out this treatment option. After receiving a transplant, you'll still need to carefully monitor your diet and overall kidney health to prevent your GFR rate from dropping too low again.

Summary:
Speak with a renal dietitian. Identify any underlying cause. Take prescription kidney medication. Discuss other medications with your doctor. Periodically check your GFR. Go on dialysis. Wait for a kidney transplant.