Synonyms: Serum creatinine, Blood creatinine, Creat, Crea, SCr, Cr, Crn

Creatinine is a chemical waste product that is produced in the muscle cells when creatine breaks down. Creatine itself is formed from amino acids in the kidneys, liver, pancreas, and then with the bloodstream travels to the muscles, brain, and nervous tissue. From muscle tissue, creatinine enters the bloodstream and is transported to the kidneys.

Interpret now "Complete Blood Count (CBC)"
Interpret now "Urinalysis (UA)"

Like urea, creatinine is removed from the blood by the kidneys and then eliminated from the body with urine. If the kidneys are not able to filter the waste products efficiently, creatinine levels in the blood will increase. High levels of creatinine may indicate kidney (renal) disorders or problems in the muscular system, where creatinine is formed. Very high levels of creatinine are toxic to the body but a little increase isn't harmful.

Normal Levels of Creatinine

Creatinine is measured in milligrams per deciliter (mg/dL) or in micromoles per liter (µmol/L). The conversion formula is mg/dL x 88.4 = μmol/L.

Creatinine concentration in blood serum depends on muscle mass, physical activity, diet, age, and sex. The normal range for a serum creatinine (SCr) is 0.7 to 1.3 mg/dL (60-115 µmol/L) for man and 0.5 to 1.0 mg/dL (45-90 µmol/L) for women. Children and women have lower levels of creatinine than men.

You must use reference values provided by the laboratory that performed your test. Normal value ranges may differ slightly among different labs. Laboratories can use different test systems and different algorithms. If you need to take a serum creatinine test several times, you should try to use the same laboratory to ensure accurate comparative results.

Creatinine in Pregnancy

During pregnancy, there is a slight decrease in creatinine levels in the first and second trimesters. Average creatinine in pregnancy is 0.6 mg/dL (53 µmol/L). Creatinine level greater than 0.8 mg/dL (70 µmol/L) should be considered outside the normal range for pregnancy.

High Levels of Creatinine

Generally, an increased serum creatinine level means some kidney diseases. Kidneys aren't able to filter all creatinine from the blood and creatinine begins to accumulate in the body. High creatinine levels may be due to infectious, autoimmune, toxic, traumatic kidney damage. Often these are chronic glomerulonephritis, pyelonephritis, diabetic nephropathy, which were not diagnosed or treated in time and led to renal failure.

Medications are filtered by the kidneys and it is important to know how your kidneys are doing before taking some medications. The most common types of medications that may need to be replaced or adjusted if your kidneys aren't working properly are pain medications, antibiotics and antiviral medications, cholesterol and diabetes medications, antacid medications.

The most common causes of high creatinine levels are diabetes, dehydration, high blood pressure, shock, bladder outlet obstruction or congestive heart failure.

Low Creatinine Levels

Low creatinine levels are usually of no concern at all. Most often low creatinine is caused by low muscle mass (can decrease with age or illness), diet (vegetarian or low-protein diet, malnutrition), pregnancy, liver problems (when a liver is not able to produce the normal amount of creatine).

Comprehensive Metabolic Panel (CMP) Interpretation