Creatinine is a natural chemical waste product found in the blood, a by-product of regular muscle activity. It is normally processed by the kidneys and excreted in urine. The levels of creatinine in your blood provide insights into both your muscle mass and kidney function.

Typically, men with healthy kidney function exhibit creatinine levels ranging from 0.6 to 1.2 milligrams/deciliters (mg/dL), while women usually have levels between 0.5 to 1.1 mg/dL. Women tend to have slightly lower creatinine levels due to differences in muscle mass compared to men.

Several factors, including body size, physical activity, and medications, can influence blood creatinine levels.

Creatinine and Chronic Kidney Disease

When kidney damage or disease occurs, and the kidneys can no longer efficiently filter waste, creatinine levels in the blood may rise. Dialysis becomes necessary when kidney function declines to a critical level. However, it’s important to note that while creatinine is a vital factor, it is just one of many considerations when determining the need for dialysis.

Symptoms of Reduced Kidney Function

In some cases, individuals may not experience any noticeable symptoms of kidney disease until elevated creatinine levels are detected in routine blood tests. When symptoms do manifest, they can include appetite loss, vomiting, itching, weakness, and flu-like sensations. Swelling in the legs and shortness of breath may also occur due to fluid retention in the body.

Creatinine Tests

Creatinine levels can be measured through blood and urine tests, which help assess changes in kidney function.

Serum Creatinine: This test involves drawing a blood sample sent to a laboratory for analysis to determine the creatinine concentration in the bloodstream. Knowing your serum creatinine level allows your doctor to calculate your glomerular filtration rate (GFR), a measure of kidney function. Using your serum creatinine level, age, and gender, you can determine your CKD stage with the American Dialysis Centers GFR Calculator. However, it’s crucial to remember that a low GFR or elevated serum creatinine alone doesn’t always indicate kidney disease, so consult your doctor for proper interpretation.

Creatinine Clearance (Ccr or CrCl): This test assesses how effectively the kidneys filter waste by measuring the amount of creatinine cleared from the body. It requires both a urine and blood sample. As urine collection spans 24 hours, creatinine clearance is typically conducted after evaluating serum creatinine and calculating GFR.

Understanding creatinine and its role in kidney health is essential in managing kidney disease and making informed decisions about your treatment plan. If you have questions or need assistance interpreting your results, consult your healthcare provider for guidance.