Can Too Much Protein Cause Bad Blood Work Results?

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Some blood tests may produce abnormal results because of what you ate or drank before the sample was drawn. The blood urea nitrogen test is one that may be altered with a high protein intake. If you are undergoing blood testing for any reason, always follows your doctor's advice about what you can eat or drink, which will provide the most accurate results, allowing for effective treatment.

Blood Urea Nitrogen Test

The BUN test measures how your kidneys and liver are working. It tests the amount of urea nitrogen in your blood. Too much could indicate your kidneys are not functioning as they should. A high BUN reading could also mean you follow a high-protein diet, which may not be healthy for everyone. Testing your BUN is often done as part of a routine blood test to determine the cause of symptoms that don't have a definitive cause. A normal BUN level for men is 8 to 24 milligrams per deciliter and a woman's BUN level should be 6 to 21 milligrams per deciliter. A result higher than 50 milligrams per deciliter indicates a potential problem.

High-Protein Diet

Many athletes and bodybuilders follow a high-protein diet as a way to support muscle strength and endurance. In this case, you might add protein powders to a diet that contains food sources of protein, such as meat and dairy foods. Following a low-carbohydrate, high-protein diet, such as the Atkins Diet, can also cause elevated BUN levels. A high-protein diet is typically one that includes 1 gram of protein per pound of body weight. Always discuss a high-protein diet with your doctor.

Test Preparation

If only your BUN levels are being tested, eat and drink as you normally would. Results are more likely to be altered by a long-term high protein intake rather than a single meal that was high in protein. Additional blood tests may require you to fast before the test, so follow the advice of the lab technician or your physician regarding how long you should go without eating before the test.


If you have an existing kidney problems, avoid high-protein diets, which can exacerbate the condition. If your blood tests indicate a high BUN level, your doctor may perform additional tests to determine if there is a medical reason for the results. It is important to tell your doctor if you eat a lot of protein so that he is able to factor that into your blood test results. Scaling back on the amount of protein in your diet will likely bring your BUN levels back to normal.