Blood and Urine Tests

Creatinine (cree-A-ti-neen) is a waste you make each time you move a muscle. Those with more muscle make more creatinine. Healthy kidneys remove creatinine from your blood. This means that a high serum (blood) level may be due to kidney damage. If your level is high, your doctor should recheck it. If two or more levels are high, you may have kidney disease.

The normal serum creatinine range is 0.6–1.1 mg/dL in women and 0.7–1.3 mg/dL in men.

This test compares creatinine in your blood and urine. The difference shows how well your kidneys work. You may need to collect your urine for 24 hours in a jug.

Normal creatinine clearance is 88–128 mL/min for healthy women and 97–137 mL/min for healthy men.

GFR is a formula that uses your creatinine, age, race, and sex. GFR is used to divide chronic kidney disease into five stages. The result is about the same as your percent kidney function. So, a GFR of 60 means you may have function that is 60% of normal.

You can use our egfr calculator to test your gfr!

Healthy adults have a GFR of about 140*; normal is greater than 90. Children and seniors tend to have lower GFRs. A GFR less than 15 is kidney failure.

*GFR is reported in mL/min/1.73 m2.

Healthy kidneys have filters (nephrons). These remove wastes but keep in large cells, like red blood cells and proteins. Albumin is one type of protein. When the filters are damaged, they may leak protein into your urine. Albumin levels can go up if you exercise a lot or have high blood sugar, too. Bladder infections can also make the levels go up.

A normal level is from 0 to about 8 mg/dL.

Rising levels in the urine can show a kidney problem. It is vital to know if your urine has protein in it!

Damaged kidneys can leak microscopic amounts of protein. These are too small to be found with standard tests—but can be an early warning sign. Special dipsticks or tests can find the protein. If you have diabetes, you are at a higher risk for kidney disease. Have a urine test for microalbumin at least once a year.

Less that 30 mg is normal. 30–300 mg may mean early CKD. More than 300 mg may mean a later stage of CKD.

Urine protein divided by creatinine gives a good sense of how much protein may leak out of your kidneys in a day. This test is not changed by how much water is in your urine.

A normal level is less that 30 mg per gram.

BUN is a measure of a waste (urea) in the blood. Your body makes urea when it breaks down protein. A low BUN may mean you are not eating enough protein. A high BUN may mean kidney function that is less than normal. Other factors may affect a BUN, too. Bleeding in the gut, heart failure, and some medicines may cause the BUN to go up. As BUN rises, you may have symptoms of kidney disease, such as a bad taste in your mouth, poor appetite, nausea, and vomiting.

The normal BUN level for healthy adults (and children) is 7–20 mg/dL.

Hct is the percent of blood that is made up of red blood cells. This test can be used to check for anemia.

The normal Hct level is 36–44% for healthy women and 40–50% for healthy men.

Hgb is the iron protein that carries oxygen and gives red blood cells their red color. Hgb is also used to test for anemia.

HbA1c is a 3-month average of your blood sugar level. If you have diabetes, have your HbA1c tested at least every 6 months.

Glucose is a sugar. Your blood sugar level is tested to see if your body can use sugar in a normal way. High levels are most often found in people with diabetes. Some medicines can also raise blood glucose levels. If your fasting blood glucose level is higher than 126 mg/dL, you have diabetes.

Normal (fasting) glucose levels are less than 100 mg/dL.

In those with diabetes, the goal before eating is 80–130 mg/dL. After eating, the goal is less than 180 mg/dL.