Proteinuria consists of excess protein in your urine, which can be an indicator of various diseases, however, low levels of protein in the urine are considered normal. This is because the protein molecules are large in size and therefore can not pass through the glomeruli or renal filters and are not normally excreted in the urine.
The kidneys filter the blood, eliminating what isn't important and retaining what is important for the body, however, in some situations, the kidneys allow the proteins to pass through their filters, causing an increase in the protein content found in your urine.
Causes and types of proteinuria
Proteinuria can occur due to several situations and, depending on its cause and how long it takes to detect the presence of protein in the urine, proteinuria can be classified as:
1. Transient Proteinuria
The situations that cause a temporary increase of proteins in the urine are:
- Emotional stress;
- Extreme cold exposure;
- Intense physical exercise.
These situations are not cause for concern, and are usually fleeting.
2. Orthostatic Proteinuria
In orthostatic proteinuria, the amount of protein in the urine increases when standing, and is usually seen in children and young people who are tall and thin. Protein secretion in the urine happens mainly during the day when activity levels are high, so if urine is collected in the morning, it should not contain protein.
3. Persistent proteinuria
Diseases and conditions that can cause high levels of protein in the urine in a persistent way can be:
- Amyloidosis, which consists of an abnormal accumulation of proteins in the organs;
- Prolonged use of some medications, such as non-steroidal anti-inflammatory drugs;
- Chronic kidney disease or polycystic kidney disease or kidney infection;
- Heart disease or infection of the inner lining of the heart;
- Hodgkin's lymphoma and multiple myeloma;
- Glomerulonephritis, consisting of inflammation of the renal glomeruli;
- Diabetes because it affects the ability of the kidneys to filter the blood or reabsorb the proteins in the blood;
- High blood pressure, which can damage the arteries located in and around the kidneys, negatively affecting the function of these organs;
- IgA nephropathy, consisting of renal inflammation resulting from an accumulation of the immunoglobulin A antibody;
- Sarcoidosis, which consists of the development and growth of inflammatory cell clusters in the organs;
- Sickle cell anemia;
- Rheumatoid arthritis.
High levels of protein in the urine may also occur in pregnancy and may be related to a number of factors, such as increased kidney work to filter excess fluid, excessive stress, urinary tract infection, or in more severe cases, preeclampsia.
Pre-eclampsia is a serious complication of pregnancy, which should be detected as soon as possible to avoid health problems in pregnant women. It may be associated with other factors such as increased blood pressure, headache, or swelling in the body.
Proteinuria can be caused by several situations, and the symptoms are not specifically related to the presence of proteins in the urine, but to the causes.
However, if proteinuria is indicative of kidney disease, other symptoms such as nausea and vomiting, decreased urine output, swelling of the ankles and around the eyes, unpleasant taste in the mouth, fatigue, shortness of breath and appetite may occur, pallor, dryness and generalized skin itching. In addition, urine may also be foamy and cause pain and burning sensation while urinating.
The treatment depends on the cause of proteinuria, so you should go to the doctor in order for the correct diagnosis to be reached, and determine what is causing the excess protein in the urine.
How is the exam done
Proteins can be readily detected in the urine with the aid of a reagent tape urine test, where the urine sample is collected and a paper strip is dipped with chemical reagents, and if the urine sample contains too much protein, the strip changes color. See what is a urine test and how is it done.
If large amounts of protein are found in your urine, a 24-hour urine test for protein measurement and creatinine clearance may be requested to help assess and control kidney function, thereby helping to detect possible diseases. Learn all about the 24-hour test.
Urine samples are collected in one or more containers for a period of 24 hours and kept in a cool place. They are then sent to a laboratory for analysis. This test does not show what types of proteins are present in the urine, so to determine the types of protein present, your doctor may advise you to perform other tests such as an electrophoresis of the proteins present in the urine.
How to prepare for the test
Before taking the exam, you should talk to your doctor in order to prepare correctly so that you don't obtain a different result. Therefore, it is necessary to stop taking some medications or supplements that may interfere with the test results.
Other factors may interfere with the test, such as dehydration or not drinking enough water, having undergone a contrast dye test in which some type of dye has been used, having been subjected to extreme emotional stress, extreme physical exercise, if you have a urinary tract infection, or if the urine is mixed with vaginal secretions, blood or semen.
If urine testing is done on women, it is very important to wait 5 to 10 days after the end of the menstrual cycle before taking the test to avoid contaminating urine with traces of blood from your period.