Hydration Test - Specific Gravity of Urine

Rebekah Kuschmider
Rebekah Kuschmider
October 18, 2023
min read
Technically reviewed by: 
Adele Morris
Hydration Test - Specific Gravity of Urine

A urine specific gravity test is a useful, non-invasive way to measure hydration levels and check certain kidney functions. Despite the name, the test doesn't have anything to do with gravity or how quickly your urine moves downward as it leaves your body. Instead, it measures the concentration of electrolytes in your urine. The level of electrolytes, along with other substances in the urine, can be used as a dehydration test at home. Since hydration levels are unique to each individual and how many glasses of water you drink per day is not the best measure of hydration, a urine specific gravity test can help you determine your actual hydration levels. Over-the-counter hydration test strips will ensure that you maintain a healthy hydration level.

What Are Electrolytes?

Electrolytes are minerals that have a natural positive or negative electrical charge when they are dissolved in water. You get electrolytes from your diet, and they include [1]:

  • Sodium
  • Potassium
  • Chloride
  • Magnesium
  • Calcium
  • Phosphate
  • Bicarbonates

Electrolytes are crucial in helping your body regulate certain chemical reactions and maintaining the balance between fluids inside and outside your cells. If you consume excess electrolytes, your kidneys filter them out of your bloodstream, and they are excreted in your urine. You can also lose electrolytes through sweating.

Replacing electrolytes can be as important as replacing fluids. Many sports drinks include electrolytes so that athletes can replace the electrolytes lost due to heat, sweat, and exertion [2].

What Is Specific Gravity of Urine?

Urine is made up of waste products from your body and water. Urine specific gravity measures the concentration of electrolytes and other substances in your urine compared to the amount of water in your urine. The tests are helpful for measuring hydration levels to ensure ideal fluid consumption for good health.

Doctors may use urine specific gravity testing to identify more serious health issues. Consistently abnormal urine specific gravity levels may indicate a need for additional urinalysis. Further testing may show high levels of substances such as bacteria, white blood cells, red blood cells, or protein. In addition, the test could show that urine is very diluted, which may indicate that your kidneys are not removing waste materials adequately [3].

Highly dilute urine can be a sign of a condition called diabetes insipidus. Diabetes insipidus occurs when the kidneys cannot conserve water. It results in excessive thirst and frequent urination. It can be due to damage to the pituitary gland or hypothalamus, which affects the production of antidiuretic hormone (ADH), a chemical that regulates fluid conservation. It can also develop due to kidney malformations. Diabetes insipidus is a serious but treatable condition [4].

Diabetes insipidus is not related to diabetes mellitus, though both conditions can cause increased thirst. Diabetes mellitus affects blood sugar levels and requires different treatment strategies.

Other underlying health conditions that can affect urine specific gravity include [3]:

Urine specific gravity reflects kidney function and hydration status, with abnormal levels potentially indicating conditions like kidney failure, infections, dehydration, heart failure, and diabetes.
Urine specific gravity reflects kidney function and hydration status, with abnormal levels potentially indicating conditions like kidney failure, infections, dehydration, heart failure, and diabetes.

What Does At-Home Urine Specific Gravity Testing Reveal?

You can use at-home test strips to measure your urine specific gravity. Using at-home urine specific gravity tests as hydration tests can let you know if you are consuming the right amount of water and electrolytes to maintain overall health, particularly in hot weather or when doing strenuous activity.

Urine specific gravity testing can be a useful hydration test for athletes who need sufficient electrolyte levels for peak performance. In addition, regular testing can be useful for people with certain health conditions who need to monitor urinary function.

Home testing can show you your urine's specific gravity so you can record it over time and understand what causes it to change.

How To Test Urine Specific Gravity at Home

Urinox-10 is a urine test strip that measures ten different parameters in urine, including specific gravity. Testing takes a few minutes, with easy-to-read color-coded results. The results can tell you if you are adequately hydrated as well as impart other information about your overall wellness.

Start by collecting a fresh urine sample in a clean, dry container. Use a "clean catch" method of collecting urine by first washing your hands and using a wipe to clean the area around your urethra. Release a small amount of urine into the toilet, then move the container into place and collect enough for testing. You may finish urinating in the toilet.

Test strips are individually packaged in sealed pouches. Remove the strip and be careful not to touch the reagent pads when handling the test strip. Immerse all of the reagent pads into the urine sample. Remove it immediately by dragging the edge of the strip against the container rim to remove excess urine. Then, place the strip horizontally on a paper towel or tissue.

The first results will develop in 30 seconds, with additional results developing according to the time listed on the color key. The specific gravity measurement will develop in 45 seconds. The specific gravity reagent pad can change color from dark green to yellowish green depending on the urine concentration, indicating your hydration level. Compare the colors of your strip to the reference chart to read your results.

Urine Specific Gravity Test Color Chart.
Urine Specific Gravity Test Color Chart.
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Normal Range of Urine Specific Gravity

Typical urine specific gravity falls in the range of 1.005 and 1.030, considered clinically normal. Results that fall slightly outside the normal range are not uncommon. The higher the number, the more concentrated your urine is. For reference, the specific gravity of plain water is 1.000.

It may appear as a broad normal range for urine specific gravity; however, given how quickly the body loses water and electrolytes during exercise, slight variations can quickly tip the scale to an abnormal level and impact performance. For example, according to one study published in the Journal of Athletic Training [5], almost half of the basketball players in the tested sample started their game in a hypohydrated state. Hypohydration refers to the hydration level lower than normal daily fluctuation, with urine specific gravity of greater than 1.020. While a hypohydration state is considered a normal clinical hydration level, sports, and exercise can lead to dehydration within minutes, suggesting the need for proper hydration strategies throughout the game/workout.

Similarly, a hyperhydrated state due to excessive intake of fluids can increase the risk of bloating, gastrointestinal discomfort, and body mass gain – all undesirable traits during sports activities. Women are often more prone to negative side effects of hyperhydration than men [6].

Low Urine Specific Gravity

A slightly low number on urine specific gravity may indicate that you have been drinking a lot and have diluted your urine. While it may be normal to have a low urine specific gravity if you have been drinking a lot of water, it may also suggest low levels of electrolytes in your body, which may make you feel exhausted and tired. Persistently low urine specific gravity could indicate that your kidneys lack the ability to filter out waste products effectively. In the case of diabetes insipidus, this could mean that kidneys cannot conserve water. This could still make you feel dehydrated despite drinking sufficient water because the body is not utilizing water. Please consult with your healthcare provider if you find yourself peeing a lot and your urine specific gravity levels are low. A clear-to-transparent urine color is another sign that your urine specific gravity is low. A normal urine color should be straw yellow.

High Urine Specific Gravity

A number slightly higher than normal may mean you have mild dehydration and need to consume more fluids. If you retake the test later in the day after adjusting your fluid intake, your result may be different.

A dark urine color (e.g., dark yellow, orange, or red) is another indication that your urine specific gravity is high. Increasing fluid and electrolyte intake and peeing as soon as you feel the urge to urinate generally resolves this issue.

However, results that are far outside the typical range may be a cause of concern, particularly if other parameters on your Urinox-10 strip also show atypical results. You may have an infection or another underlying condition.

Final Words

The specific gravity of urine is a very useful and versatile measurement that not only checks your body's hydration levels, it also aids in the diagnosis of several hidden diseases. You can use this hydration test to achieve peak physical performance in your exercise and sports. Both overhydration and underhydration have negative effects on your physical performance and health. 

Doctors frequently consider urine specific gravity measurements to understand your health and the condition of your internal organs. If you have urine specific gravity results that are persistently outside the normal range, speak to your doctor. You may need additional testing and treatment.

Make hydration testing a part of your wellness routine to stay informed of your body's hydration needs and achieve peak physical performance in your sports and workout sessions by staying optimally hydrated – a balance between overhydrated and underhydrated.

  1. I. Shrimanker and S. Bhattarai S, "Electrolytes," StatPearls, Available online here. [Accessed September 4, 2023].
  2. Cleveland Clinic, "Electrolytes," Available online here. [Accessed September 4, 2023].
  3. R. Nail, "Urine Specific Gravity Test," HealthLine. [Accessed September 4, 2023].
  4. C. Slightham, "Everything You Should Know About Diabetes Insipidus (DI)," HealthLine. [Accessed September 4, 2023].
  5. Osterberg KL, Horswill CA, Baker LB. Pregame urine specific gravity and fluid intake by National Basketball Association players during competition. J Athl Train. 2009 Jan-Feb;44(1):53-7. Available Online
  6. Silva RP, Mündel T, Altoé JL, Saldanha MR, Ferreira FG, Marins JC. Preexercise urine specific gravity and fluid intake during one-hour running in a thermoneutral environment - a randomized cross-over study. J Sports Sci Med. 2010 Sep 1;9(3):464-71. Available Online.

About the Author
Rebekah Kuschmider

Rebekah has been writing about culture, health, and politics since 2010. She has a masters degree in Arts Policy and Administration from The Ohio State University. Her work has been seen at WebMD, The Candidly, MedicineNet, YourTango, Ravishly, Babble, Scary Mommy, Salon, Role Reboot, The Good Men Project, SheSaid, Huffington Post, and Mamamia. She is a former cohost of the weekly podcast The More Perfect Union. Rebekah lives in Maryland with her husband, two kids, and a dog who sheds a lot.

About the Reviewer
This blog was
Technically reviewed by: 
Adele Morris

Adele Morris served as the editor and proofreader of this blog, displaying her exceptional editorial skills and expertise in the field.

The blog was also reviewed by the Diagnox content team. Diagnox Staff consists of a multidisciplinary team of scientists, content writers, and healthcare professionals with an expertise to create and review high-quality, informative, accurate, and easy-to-understand content for both professionals and everyday readers. Our staff follows strict guidelines to ensure the credibility and authenticity of the information, reviewing them independently and verifying them by various scientific and technical sources to ensure accuracy. Our review team believes in delivering knowledge free from bias to improve public health and well-being.

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