A urine protein test measures the amount of protein in a urine sample. A doctor may suggest this test to help evaluate and monitor kidney function and potentially detect kidney damage.

The kidneys play an important role in removing waste products and excreting them as urine. Compounds that the kidneys remove include urea, uric acid, and drugs and their metabolites. Urine should not contain a significant amount of protein.

When large quantities of protein are present in the urine, this may suggest the kidneys are not working correctly or that there is a high level of protein in the blood. If a healthcare professional suspects a problem with the kidneys, they may advise a urine protein test.

Read on to learn more about urine protein tests.

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A urine protein test is a medical examination that measures the amount of protein in a person’s urine.

The term proteinuria describes an excessive level of protein in the urine. The presence of protein in the urine beyond a certain limit may indicate problems with the kidneys or another underlying health condition.

A doctor may suggest a urine protein test as part of a routine checkup. However, in many cases, a healthcare professional may recommend a urine protein test if they suspect that the kidneys are not functioning correctly.

The kidneys play a crucial role in filtering waste products and excess substances, including proteins, from the blood. They may filter small amounts of protein into the urine. However, as most protein molecules are too large to pass through the filters, protein in the urine is not a typical occurrence.

If there are problems with the filtration process of the kidneys, excess protein can leak into the urine.

Symptoms that may suggest kidney damage include:

Typically, a person does not need to do any special preparation for a protein urine exam. If necessary, a doctor will provide guidelines for how to prepare for the test. These may include maintaining adequate hydration, following dietary guides, and avoiding any strenuous exercise.

Additionally, a healthcare professional will likely ask about any health conditions and any medications or supplements a person takes. This is because these factors could affect the results of the test.

For a protein urine test, a medical team may require either a single sample or multiple samples over a 24-hour period. Typically, a doctor will request a 24-hour urine sample as a follow-up test if the single sample shows a large amount of protein in the urine.

Also known as a dipstick test, the one-time sample test involves collecting a single urine sample in a sterile container. The kit to collect the sample will typically contain instructions to help an individual collect a suitable sample.

For example, it may include instructions on how to collect a clean catch sample. This refers to urinating a small amount into the toilet bowl, stopping the flow of urine, then collecting a sample until the container is half full. This is because the initial stream of urine may contain contaminants.

The instructions may also advise collecting a urine sample in the morning, as it will contain more concentrated urine.

After collecting the sample, a healthcare professional will place a dipstick with a color-sensitive pad into the sample. The dipstick will change color to indicate the presence of protein.

As the name suggests, a 24-hour urine sample is simply a collection of all urine a person passes over a 24-hour period of time.

Often, it involves recording the time of the first urination of the day but not collecting a sample. A person will typically then collect each subsequent urine sample, record the time, and refrigerate the samples. The samples will then go to a laboratory where a lab technician will measure the amount of protein in each one.

A small amount of protein in the urine is typical. However, an elevated protein level may indicate a problem. Often, a high level of protein in the urine suggests kidney damage or kidney disease. In these cases, urine protein tests can monitor kidney health.

An increasing amount of protein over time generally indicates increasing damage and decreasing kidney function.

However, a higher protein level may not always indicate a health issue. For example, certain medications, dehydration, stress, or strenuous exercise can raise the level of protein in the urine.

Additionally, some individuals may have proteinuria in the day but not at night. This may indicate orthostatic proteinuria, which is when protein leaks into the urine when a person stands upright.

A urine protein test involves measuring the amount of protein present in a urine sample. A doctor may request this test to assess kidney function and identify potential health issues.

As the kidneys do not typically allow large quantities of protein to pass into the urine, the presence of protein may suggest a problem with the kidneys.