Is Clear Urine a Sign of Kidney Failure?
Our content is not intended nor recommended as a substitute for medical advice by your doctor. Use for informational purposes only.
The short answer:
Clear urine can be a sign of kidney disease. However, not every clear urine is considered a sign of kidney failure. Most cases of clear urine are due to non-renal conditions such as excess water intake, pregnancy, caffeine, diuretics, or diabetes.
- Clear (colorless or watery-like) urine is often a result of excess urine (polyuria).
- Clear urine can be a sign of kidney failure in some cases, such as chronic kidney disease, adult polycystic kidney disease, chronic lithium use, and others.
- However, most cases of clear urine are due to non-renal causes such as excess water intake, caffeine, excess alcohol, pregnancy, diabetes mellitus, and diabetes insipidus (the central type).
- So, Most causes of clear urine are unlikely to be due to kidney failure.
- Only worry about clear urine if it is associated with other signs of kidney failure, such as shortness of breath, nausea, vomiting, fatigue, or the inability to lie flat.
Table of Contents
Why does clear urine rarely indicate kidney failure?
Clear urine (colorless or water-like pee) typically indicates polyuria rather than kidney failure. Most causes of clear urine are related to excess water excretion by the kidney (polyuria).
Polyuria (resulting in clear urine) is not a sign of kidney failure in general. It occurs due to a wide variety of conditions and diseases. Most of them are not related to kidney failure.
Clear urine can be a sign of kidney disease in rare cases such as:
- Nephrogenic Diabetes insipidus.
- During the healing stage of some kidney diseases (such as acute tubular necrosis).
A. Nephrogenic diabetes insipidus:
It is considered a kidney disease (not a kidney failure, but a kidney defect leading to the kidney’s defective ability to concentrate urine.
Nephrogenic diabetes insipidus occurs due to kidney resistance to the antidiuretic hormone (ADH), which is necessary to control the amount of urine.
Common causes of nephrogenic DI:
- Genetic mutations (inherited from parents).
- Chronic kidney diseases: bilateral urinary tract obstruction, sickle cell disease, Sjogren’s syndrome.
- Polycystic kidney disease.
- Chronic lithium use and Nonsteroidal anti-inflammatory drugs (NSAIDs).
- Renal amyloidosis.
- Severe hypercalcemia.
- Severe hypokalemia.
Clear urine can be a sign of kidney disease. However, not every clear urine is considered a sign of kidney disease. Most cases of clear urine are due to non-renal cases such as excess water intake, pregnancy, caffeine, diuretics, or diabetes.
B. Clear urine can be a sign of healing from kidney disease.
Recovery from an acute renal disease may present with polyuria and clear urine due to the secretion of excess urea accumulated in the body during the acute failure stage.
For instance, acute kidney injury, such as pre-renal failure due to dehydration and acute tubular necrosis, typically passes into two phases:
- The oliguria/anuric stage: during the disease, the kidney stops working partially or completely, leading to peeing too little urine or a complete lack of urine (anuria).
- The Polyuric (healing) stage: after recovery of the kidney from the acute disease, the kidney starts to work again, leading to the passage of frequent and clear urine.
In such a case, clear urine is a sign of healing from a kidney disease rather than a permanent damage sign.
When “clear urine” is NOT a sign of kidney failure.
Transient or intermittent attacks of clear urine are unlikely to be due to kidney disease. Many conditions, dietary and drinking habits may lead to polyuria and subsequent clear (colorless or pale urine).
These conditions are more common and responsible for most cases of clear urine:
- Excess water intake (some people prefer to stay hydrated and drink excess water beyond the body’s needs).
- Psychogenic polydipsia.
- Excess alcohol intake (binge drinking).
- Excess caffeine (caffeine is a potent diuretic that leads to frequent clear urine).
- Undiagnosed diabetes mellitus (high blood sugar is filtered through the kidney, withdrawing more water from the body into urine, leading to polyuria and clear urine).
- Uncontrolled diabetes mellitus (high blood sugar in patients with known diabetes but not compliant with treatment or diet).
- Diuretic medications intended to increase urine volume (such as furosamide and thiazide diuretics).
- Other medications that may cause polyuria and clear urine as a side-effect include antidiabetics, antihypertensive, antidepressants, and others.
- Central diabetes insipidus: deficiency of antidiuretic hormone (secreted inside the brain), the deficiency of ADH hormone leads to the inability of the kidney to concentrate urine (excess crystal clear urine). ”This type of DI is due to a lesion in the brain (hypothalamus) rather than a kidney disease).
- Cushing’s syndrome.
- Excess IV fluids.
- Mannitol and hypertonic saline (Brain dehydrating solutions) are used for patients with brain conditions such as cerebral hemorrhage.
- High protein intake.
Many causes of clear urine and polyuria are not related to kidney disease. So, no need to worry about clear urine unless it is persistent or associated with other worrisome symptoms such as vomiting, severe headache, shortness or breath, etc.
How to tell if you have kidney failure?
Kidney failure can be acute or chronic. Not all kidney diseases lead to kidney failure.
Acute kidney failure is a sudden deterioration of a kidney function within days or weeks. It is commonly caused by medications, hemorrhage, surgery, or severe illness.
Chronic kidney failure (End-stage renal disease) refers to the gradual and permanent loss of kidney function for months or years.
Clear urine can be a sign of healing from acute kidney failure or a sign of chronic kidney failure (if it is persistent for months).
Here is how to tell if your clear urine is due to kidney failure (symptoms):
A. Symptoms of acute kidney failure:
- Decreased output (sometimes, the urine output remains normal or even increases).
- Shortness of breath.
- Inability to lie flat.
- Nausea, vomiting.
- Fatigue, Dizziness.
- Chest pain or pressure.
- Seizures or coma.
- Swollen legs, ankles, feet, or eyelids.
- Dark or foamy urine.
Some cases of acute kidney failure pass into an oliguric stage (little or no urine), then the urine output increases resulting in clear urine (the polyuric stage). In such a case, clear urine is considered a sign of healing from acute kidney failure.
B. Symptoms of chronic renal failure:
- Nausea, vomiting, anorexia.
- Chronic fatigue and weakness.
- Shortness of breath.
- Sleep problem.
- Urinating more or less.
- Muscle cramps and bone pain.
- Dry, pale, and itchy skin.
- Lack of concentration, chronic headache.
- High blood pressure (often resistant to treatment).
- Chest pain.
How does your doctor diagnose kidney failure?
Your doctor diagnoses kidney failure based on symptoms, laboratory, and imaging findings denoting kidney failure. Clear urine is not a specific sign that denotes kidney failure.
To diagnose kidney failure, your doctor will:
A. Take a medical history and perform a clinical exam.
Your doctor will take a comprehensive medical history regarding acute and chronic renal failure symptoms, drug history, and any chronic diseases.
Then, he will perform a clinical examination, including your vital signs (pulse, blood pressure, etc.), abdominal, chest, and radiological examination.
B. Request laboratory tests to evaluate the kidney function:
- Urine analysis and culture.
- Urine albumin and urine sodium.
- Serum urea and creatinine.
- An arterial blood gas test.
- Complete blood count (CBC).
- And others.
C. Request imaging studies to detect any kidney damage:
- Abdominal ultrasound.
- Plain erect x-ray of the urinary tract.
- CT or MRI.
Kidney failure is often present when there are elevations in serum urea and creatinine.
Your doctor may perform further investigations to detect the cause, such as a kidney biopsy, drug screen, etc.