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Tests for Renal Insufficiency

Renal insufficiency refers to the inability of the kidneys to adequately perform their functions. MedlinePlus refers to it as chronic kidney disease that develops slowly over time, taking months or years. Symptoms may not occur until kidney function decreases to 10 percent of normal. Numerous tests are available to measure kidney function and determine the extent of renal insufficiency.

  1. Blood Pressure

    • High blood pressure, or hypertension, is a symptom of renal insufficiency. The National Kidney Foundation recommends testing for high pressure as part of screening for kidney disease because high blood pressure is almost always present in chronic kidney disease. High blood pressure can be the result of renal artery disease, which is a narrowing of the arteries leading to the kidneys. This narrowing restricts blood flow to the kidneys; the kidneys respond by secreting a hormone that increases blood pressure in an attempt to increase blood flow.

    Urine Test

    • A urine test, or urinalysis, can detect renal insufficiency six months to 10 years before symptoms appear, according to MedlinePlus. The test identifies proteins, including a specific blood protein called albumin. In the initial stages of renal insufficiency, only a small amount of albumin will be present in the urine. As kidney function declines, the amount of albumin increases. Another substance identified in urine tests is creatinine, a normal waste product. Healthy kidneys remove it from the blood and place it in urine. As kidneys fail, it remains in the blood. So high creatinine levels in the blood and low levels in the urine indicate that the kidneys are failing.

    Glomerular Filtration Rate

    • Glomerular filtration rate, or GFR, involves measurement of creatinine levels in the blood. Those levels are then combined with the patient's age, sex and race. The medical community identifies five stages of renal failure based upon GFR scores. Stage 1 is slight damage to kidney function while Stage 5 requires dialysis or kidney transplant.

    Other Tests

    • Kidney imaging using cat (CT) scans, ultrasounds or MRIs identifies damage to the kidneys. A blood urea nitrogen (BUN) measures levels of urea, a waste product, in the blood. Normal kidney function removes urea from the blood and transfers it to urine. Above normal urea levels in the blood indicates renal insufficiency.

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