05/24/2012 04:16 pm ET Updated Jul 24, 2012

Kidney Disease: To Screen or Not to Screen? That Is the Question

When it comes to screening for various diseases, an ounce of prevention was always thought to be worth a pound of cure. Recently, this old adage has been called into question. While potentially lifesaving, many health screening tests and procedures come at great emotional, physical and financial cost. At what point do these costs outweigh the benefits? Or vice versa? From the lens of a kidney doctor, where does screening for kidney disease fit into this larger picture? Should everyone be routinely screened or should screening be targeted to specific groups? Do the benefits of screening for kidney disease outweigh the costs?

The answer is both yes and no. Yes, there are many significant benefits of screening and early detection of kidney disease, but no, not everyone should be or needs to be screened.

It is recommended by the National Kidney Foundation that we screen everyone who has a high likelihood and/or is at increased risk of developing chronic kidney disease. This means that anyone who has high blood pressure, diabetes or a family history of chronic kidney disease should be screened. Diabetes and high blood pressure damage the kidneys over time. Often there aren't any physical symptoms associated with this kidney damage, so people with either of these conditions should be tested for kidney disease on a regular basis. While population-wide screening is not currently recommended, as the number of people with these risk factors spiral higher, the gap between those at risk and the general population narrows. We're talking about screening 1 in 3 Americans, or roughly 74 million who are at risk because of hypertension and/or diabetes.

When detected early, chronic kidney disease (CKD) can be slowed, and often more serious complications can be prevented. Many CKD patients, especially those with diabetes and heart disease, may be able to delay or avoid going on dialysis or ever needing a kidney transplant when kidney disease is detected and managed early on.

Additionally, as we age, the kidneys tend to work less effectively. If you are over 60 years old, you have a higher rate of developing CKD. While some decrease in function is normal, often people don't realize that even in the elderly population kidney function should be monitored over time to ensure that the kidneys are working properly. If you have heart or peripheral vascular disease (hardening of the arteries), you also have a greater risk of developing CKD. If you are African American, Asian, Hispanic, American Indian or Pacific Islander, then you also have a greater risk of developing chronic kidney disease. Obesity in the United States is rising rapidly and also increases the risk of CKD.

How do you screen for kidney disease?

There are two simple tests that are quick, easy and routinely performed to screen for chronic kidney disease: a blood kidney function test for creatinine and a kidney damage test for protein in the urine.

1. Creatinine is a waste that healthy kidneys filter out of the blood. The creatinine level in the blood reflects how well the kidneys are filtering these wastes and can vary depending on age, race and body size. The serum creatinine (blood) level is used to estimate how well the kidneys filter. The estimated glomerular filtration rate or eGFR is a number that you can think of as a percentage of how well your kidneys are functioning. Above 90 is considered normal and below 60 for three or more months is chronic kidney disease.

2. Protein in the urine is an early sign of chronic kidney disease. Persistent amounts of protein in the urine (proteinuria) indicate kidney damage. Normal is less than 30 milligrams of albumin (a type of protein) per gram of urinary creatinine. Greater than 30 milligrams per gram is abnormal. If there is an abnormal level of protein in the urine, it indicates that when filtering wastes from the blood, the kidneys are relegating protein to the "discard pile" rather than recycling it back into the body. The protein then leaves the body in the form of urine, which is why this test can detect kidney damage.

Together, these two screening tests determine how well your kidneys are filtering wastes from the blood and whether products that should remain in the body, such as protein, are being leaked into the urine. Because these are relatively non-invasive, inexpensive tests and because early detection can prevent further kidney damage, I and the National Kidney Foundation recommend that all people with risk factors be screened for chronic kidney disease.

To screen or not to screen: What's the bottom line?

If you have any of the risk factors mentioned above, you have a 1 in 3 chance of developing chronic kidney disease. It is very likely that you are either part of this 33 percent or know someone who is. If so, get screened to make sure your kidneys are working as they should be and to prevent further kidney damage!

Ask your doctor for these tests during your next visit or attend the National Kidney Foundation's free kidney health screening program called the Kidney Early Evaluation Program (KEEP). KEEP provides free testing in communities across the country for those at risk of developing chronic kidney disease

For more by Leslie Spry, M.D., FACP, click here.

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