What is creatinine?
Creatinine is a waste product from normal muscle metabolism. Your kidneys remove it from the blood, so serum creatinine is commonly used to help estimate kidney filtration.
Creatinine is not a perfect stand-alone measure. Muscle mass, diet, supplements, medications, and other factors can affect the value. Laboratories therefore use creatinine with other information to calculate an estimated glomerular filtration rate, or eGFR.
Why might creatinine be elevated?
- Dehydration or acute illness can temporarily reduce kidney filtration.
- Acute kidney injury can occur with severe illness, infection, surgery, obstruction, or other stresses on the kidneys.
- Chronic kidney disease can cause persistently reduced filtration.
- Medications and supplements can affect kidney function, creatinine handling, or interpretation of kidney tests.
- Higher muscle mass, recent strenuous exercise, creatine supplements, and a recent large meat meal can influence creatinine in some people.
Creatinine and eGFR: why physicians look at both
eGFR estimates how well the kidneys filter blood and is generally more informative than serum creatinine alone. It is still an estimate, and creatinine-based eGFR can be less accurate when kidney function is changing rapidly or muscle mass is unusual.
Two key markers for chronic kidney disease are eGFR and urine albumin. A urine albumin-to-creatinine ratio (UACR) is commonly used to look for albumin leakage from the kidneys.
Why the trend matters
A stable creatinine over time can mean something very different from a rapid rise over several days. Chronic kidney disease generally requires abnormalities of kidney structure or function to be present for at least 3 months; one abnormal result alone does not establish chronic kidney disease.
Illustration only—not a diagnostic chart or treatment threshold.
What else may be checked?
Depending on the situation, evaluation may include repeat creatinine/eGFR, urinalysis, UACR or another urine protein measurement, electrolytes, blood pressure, medication review, diabetes assessment, and sometimes kidney imaging or additional testing.
When might kidney-specialist evaluation be appropriate?
Consider earlier kidney evaluation—not just advanced disease.
At AspireMed, Kashif Abad, MD, MBA, FACP, generally recommends considering nephrology evaluation when eGFR is persistently below 60 mL/min/1.73 m², particularly when the cause is unclear or other kidney-related abnormalities are present.
Nephrology evaluation may also be appropriate at a higher eGFR when there is significant protein or blood in the urine, rapidly declining kidney function, difficult-to-control hypertension, recurrent electrolyte or acid-base abnormalities, or another concern for kidney disease.
An eGFR below 60 does not automatically mean kidney failure. Results should be interpreted with chronicity, urine findings, previous kidney function and the overall clinical picture.
This reflects AspireMed's proactive clinical approach and should not be interpreted as a universal mandatory-referral threshold. Formal kidney-care referral recommendations also consider cause, albuminuria, hematuria, rate of decline, kidney-failure risk and other clinical circumstances.
Learn more about AspireMed's Kidney & Blood Pressure Care.
When should an abnormal kidney test be evaluated urgently?
Seek prompt medical evaluation when an abnormal kidney result occurs with severe or rapidly worsening illness, markedly decreased urine output, significant swelling or shortness of breath, persistent vomiting or inability to keep fluids down, confusion, severe weakness, or other concerning symptoms. Severe electrolyte abnormalities or rapidly worsening kidney function may also require urgent treatment even before symptoms become obvious.
If you believe you are experiencing a medical emergency, call 911 or go to the nearest emergency department.
Common questions
Can dehydration raise creatinine?
Yes. Dehydration can contribute to a temporary reduction in kidney filtration and a rise in creatinine. But an elevated creatinine should not automatically be attributed to dehydration without considering the rest of the clinical picture.
Will drinking more water lower creatinine?
Not necessarily. Correcting dehydration may improve kidney measurements when dehydration is the cause, but excessive water does not “flush out” chronic kidney disease and may be inappropriate for some people.
Can medications affect creatinine?
Yes. Some medicines can affect kidney function or creatinine. ACE inhibitors, ARBs, and SGLT2 inhibitors can cause an expected early change in creatinine or eGFR while providing important kidney or cardiovascular benefits in appropriate patients. Do not stop prescribed medication solely because of one laboratory result; discuss it with the prescribing clinician.
What creatinine level is dangerous?
There is no single creatinine number that is dangerous for every person. Baseline kidney function, eGFR, rate of change, muscle mass, urine findings, electrolytes, symptoms, medications and the underlying cause all matter.
Can creatinine improve?
Sometimes. Creatinine may improve when a reversible cause is identified and treated. With chronic kidney disease, the goals may instead include identifying the cause, protecting remaining kidney function and slowing progression.
Putting it together
A high creatinine does not automatically mean kidney failure. Think beyond one number: creatinine and eGFR, previous results, urine albumin, blood pressure, medications, medical conditions and symptoms together provide a more useful picture of kidney health.
Kashif Abad, MD, MBA, FACP
Internal Medicine & Nephrology · AspireMed
References & further reading
Clinical framework reviewed against the KDIGO 2024 Clinical Practice Guideline for the Evaluation and Management of Chronic Kidney Disease and NIDDK resources on eGFR, urine albumin, and kidney disease evaluation. NIDDK web resources accessed September 17, 2026.
KDIGO — CKD Evaluation and Management
NIDDK — Identify & Evaluate Patients with CKD
NIDDK — Quick Reference on UACR & GFR
Need an individual kidney evaluation?
Educational information cannot determine the cause of an abnormal laboratory result. AspireMed provides physician-led kidney and blood pressure care for adults, including telehealth when clinically appropriate.