Creatinine is a waste product generated continually by the normal breakdown of muscle tissue. A blood test revealing a creatinine level of 1.7 milligrams per deciliter (mg/dL) indicates an elevation outside of the typical reference range. This number signals a change in how the body processes waste and warrants medical attention. This information provides context for this specific lab result and details the necessary steps for evaluation and management.
What Creatinine Is and Normal Ranges
Creatinine is a byproduct of creatine, an organic compound stored in muscle cells that provides energy for muscle contraction. Since muscle mass is relatively stable, creatinine production remains constant. Healthy kidneys continuously filter this waste product from the blood, primarily through the glomeruli, before excreting it in the urine.
The serum creatinine test measures the concentration of this waste remaining in the blood. For most healthy adults, the normal range typically falls between 0.6 to 1.2 mg/dL. This range varies based on individual characteristics; males and muscular individuals often have naturally higher levels due to greater muscle mass. Conversely, individuals with lower muscle mass, such as those of advanced age, may have a lower “normal” level. A result of 1.7 mg/dL represents a notable elevation beyond the standard healthy range for the majority of the population.
The Significance of a 1.7 Result
A reading of 1.7 mg/dL indicates that the kidneys are not filtering waste efficiently. This significance relates directly to the Glomerular Filtration Rate (GFR), the definitive measure of kidney function. A high creatinine level suggests a reduction in the GFR, meaning the blood is not being adequately cleared of waste products.
To accurately assess filtering capacity, clinicians use the estimated Glomerular Filtration Rate (eGFR) calculation. This formula incorporates the serum creatinine level along with factors like age, sex, and body size. A creatinine of 1.7 mg/dL for an adult often correlates with an eGFR that places the person in Chronic Kidney Disease (CKD) Stage 3.
CKD Stage 3 is defined by an eGFR below 60 mL/min/1.73m² for three months or longer. For many men, this result may represent a reduction to approximately 50% of normal kidney function. While 1.7 mg/dL is not an immediate medical emergency, it signals a substantial loss of function that requires prompt investigation to determine if the cause is acute or chronic.
Non-Kidney Reasons for Elevated Levels
An elevated creatinine level of 1.7 mg/dL does not automatically confirm chronic kidney damage. Several temporary, non-renal factors can cause the level to rise by affecting either the production or elimination of creatinine. One common cause is severe dehydration, which concentrates the blood and reduces the fluid available for the kidneys to excrete, leading to a temporary buildup.
Other factors include a high-protein diet, especially consuming cooked meat shortly before the blood draw, which temporarily spikes the measured level. Intense exercise or the use of creatine supplements can also elevate the circulating waste product. Certain medications can interfere with the test result without harming the kidneys. For instance, trimethoprim and cimetidine can inhibit the kidney tubules from actively secreting creatinine into the urine, causing a reversible, artificial increase that returns to normal once the medication is stopped.
Required Follow-Up and Management
Receiving a 1.7 mg/dL result necessitates a structured follow-up plan to confirm the reading and assess the underlying cause. The physician will order a repeat blood test, often after ensuring the patient is well-hydrated and has avoided high-protein foods or intense exercise. Additional blood work, such as a Blood Urea Nitrogen (BUN) test and an electrolyte panel, provides further insight into waste clearance and checks for imbalances.
A urinalysis is an important next step, specifically looking for protein or albumin in the urine, which signals kidney damage. The albumin-to-creatinine ratio (ACR) is a sensitive measure used to detect early signs of leakage. Imaging studies, such as a renal ultrasound, may also be used to visualize the structure of the kidneys and check for blockages. Management strategies focus on addressing underlying conditions and protecting remaining kidney function. This includes rigorous control of blood pressure (targeting below 130/80 mm Hg) and optimizing blood sugar control if diabetes is present.