The purpose of screening is early diagnosis and treatment. Screening tests are usually administered to people without current symptoms, but who may be at high risk for certain diseases or conditions. Individuals with the following conditions are at high risk:

Early diagnosis and treatment of chronic kidney disease can prevent or delay complications. Since significant kidney disease is usually associated with a decrease in GFR and/or leakage of protein in the urine, the National Kidney Foundation recommends the following screening tests for people at increased risk for chronic kidney disease:

Blood Creatinine Level

Creatinine is a waste product that the kidneys usually remove from the blood. When the kidneys are damaged, the creatinine level rises. A simple blood test can measure the creatine level, which is also used to calculate the glomerular filtration rate.

Estimated Glomerular Filtration Rate

The glomerular filtration rate (GFR) is a measurement of how well the kidneys are processing wastes. Your doctor can calculate the GFR based on your:

  • Sex
  • Age
  • Body size
  • Blood creatinine level

The usual formula your doctor uses to estimate GFR is called the Cockcroft-Gault equation:

Estimated GFR (mL per minute) = (140 – age) X body weight in kilogram ÷ 72 X serum creatinine. This product is multipled by 0.85 if estimation is for a female patient.

The GFR determines the stage of chronic renal disease.

Stage Glomerular Filtration Rate (GFR)
1Over 90 mL/min (normal)
260 to 89 mL/min(mild decrease)
330 to 59 mL/min (moderate decrease)
415 to 29 mL/min (severe decrease)
5under 15 mL/min (kidney failure)

Urine Protein Level

During the filtering process, the kidneys usually return protein to the circulation. With chronic kidney disease, the kidneys allow protein to leak into the urine. Different kinds of proteins can leak into the urine. Albumin is a protein that often appears in the urine of people who have chronic kidney disease caused by high blood pressure or diabetes.

The guidelines of the National Kidney Foundation recommend two tests to check the urine protein level:

  • Protein-to-creatinine ratio
  • Albumin-to-creatinine ratio

To perform these tests, the laboratory compares the amount the protein or albumin to the amount of creatinine in a urine sample.

Depending on your risk factors, your doctor may also order the following screening tests:

Serum Electrolytes

Electrolytes, such as sodium and potassium, are minerals needed for the body to work well. Chronic kidney disease causes changes in the electrolytes. A simple blood test can measure the levels of these substances.

Urine Concentration

Chronic kidney disease causes changes in the concentration of the urine. A simple test can measure the urine concentration.

Urine pH

Chronic kidney disease causes changes in the pH, or acid level, of the urine. A simple test can measure the urine pH.