Protein in Urine Lab Values

Hey everyone, Abby, here from nursing.com. In this lesson, we’ll talk about a urinalysis that monitors for protein in the urine, what normal values should be when it might be increased or decreased, and why we would draw this lab. Let’s dive in! 

Protein is evaluated in the urine for a condition called proteinuria. What it does is it’s a urine analysis that evaluates the presence and the amount of protein in a urine sample. It’s usually measured with a dipstick like this one. Now, a small amount of protein is normal to be excreted in the urine every day, but truly there shouldn’t be much protein in the urine. Proteins are an integral part of various processes in the body like building muscle, regulating, repairing, signaling, and transporting. They should really remain in the blood and not enter the urine where they can be excreted. 

There are four main types of proteinuria. The first is glomerular proteinuria. That’s when there’s going to be glomerular damage. That means that the vessels in the glomeruli are leaky and they’re letting proteins out to go into the urine, as opposed to being resorbed into the blood. Tubular proteinuria is secondary to incomplete resorption. So, it can be a problem within the tubules as well. Overflow proteinuria is a manifestation from certain disorders or cancers like multiple myeloma where short-chain really small proteins are rapidly created, and they’re so tiny that they get excreted out into the urine. Post-renal proteinuria is due to urinary tract infection and the presence of white blood cells or leukocyturia. 

Some clinical indications for having this proteinuria evaluation are, if someone has chronic kidney disease, it can really help with staging based on the amount of protein present. It’s also evaluated in someone that’s pregnant that has hypertension because we suspect preeclampsia. 

But remember,  it can’t be termed preeclampsia on hypertension alone. It also has to have proteinuria present in the clinical presentation. Glomerulonephritis, or an inflammation of the glomeruli, is going to spill out proteins, just like we talked about with those leaky vessels. And, it’ll go into the urine instead of being resorbed into the blood in kidney transplant, autoimmune diseases, diabetes, and cardiac disease. These are all indications of damage or abnormalities with filtration in the body and can result in protein getting into the urine. 

Normal therapeutic values are zero to trace amounts. Remember how I said that a small amount of protein being excreted is normal every day, but if it exceeds 150 milligrams, that’s when it’s termed proteinuria. We talked about the collection with a urine dipstick analysis. It would be taken in a sterile specimen cup like this one. There’s also the sulfosalicylic acid test, which detects non-albumin proteins, whereas the normal urinalysis pretty much takes albumin into account the most. A sample can also be taken off of catheter tubing, and shouldn’t be taken out of the bag. We want to know exactly what’s coming out of the bladder. Not what’s had a chance to sit in that nasty little bag. It can also be evaluated after a 24-hour urine collection in urinalysis. 

Proteinuria or the presence of protein will be increased long term in those with either an acute kidney injury or chronic kidney disease. Those with diabetes because increased blood glucose is so irritating to the glomeruli, also, with cardiac disease and hypertension. Think about all that pressure on those little tiny arterials and venules within the glomeruli. Also, we talked about lupus, which is one of the autoimmune diseases, lots and lots of inflammation, as well as all of that creation of those short chain proteins in multiple myeloma. Shorter term increases will be due to hemolysis. Hemolysis is when that red blood cell gets all blasted and it’s going to release its components into the bloodstream, and those are going to be proteins and they can then be filtered out into the urine. We talked about preeclampsia, which also has to be combined with hypertension. It can also be increased in times of trauma and dehydration. Low levels are not associated with disease or disorders but, what is indicative is if it’s measured after an acute episode of proteinuria decrease levels, show that there has been a resolution to the problem. Now, protein and urine is evaluated via urinalysis. We want to evaluate for kidney function. Anything less than 150 milligrams is normal, but truly zero to trace is what we’re looking at. Anything greater than 150 milligrams is proteinuria and can indicate acute or chronic kidney disease, dehydration, and don’t forget preeclampsia. If the value is decreased, which is what we’re going for, that could mean that an acute disturbance is resolving. That’s what we want. Now you did great on this lesson. This wraps it up. We love you guys, now go out and be your best self today and as always, happy nursing.

References:

• https://my.clevelandclinic.org/health/diseases/16428-proteinuria#:~:text=What%20is%20proteinuria%3F,should%20remain%20in%20the%20blood.
• https://www.uptodate.com/contents/urinalysis-in-the-diagnosis-of-kidney-disease?search=proteinuria&source=search_result&selectedTitle=8~150&usage_type=default&display_rank=8#H3496515220
• https://www.uptodate.com/contents/glomerular-disease-evaluation-and-differential-diagnosis-in-adults?search=proteinuria&sectionRank=1&usage_type=default&anchor=H4248130478&source=machineLearning&selectedTitle=4~150&display_rank=4#H4248130478
• https://www.kidneyfund.org/all-about-kidneys/other-kidney-problems/protein-urine#:~:text=Causes%20of%20short%2Dterm%20protein%20in%20the%20urine,-Health%20problems%20that&text=Dehydration%20(not%20having%20enough%20water,Fever
• http://www.nursing.com