#rn2018

So, what the heck is creatinine, even?!

Everybody in nursing school had heard the term creatinine. We know that it has to do with your kidneys and, from what our teachers have told us, it’s a major lab value to know. However, what is it and how/why do we evaluate it? 

What Creatinine Is

To understand creatinine, we need to know what its origin is: creatine. Creatine helps to produce adenosine triphosphate (ATP). ATP is what gives our cells energy. We store creatine in our muscles and bones. When we perform exercises or body build, some creatine is converted, then, to creatinine. Roughly, only 2% of our creatine makes creatinine. 

Creatinine is the waste product resulting from creatine. Our bodies only excrete creatinine through the kidneys. That’s why there is a parallel between creatinine levels and kidney functions. Creatinine can be affected by a couple things, though. Generally, the more muscle mass on a person, the higher their creatinine will be. However, keep in mind our blood creatinine is measured in decimal points. So the difference is not seen drastically. 

Who do you think has higher creatinine levels? :)

While we’re not supposed to have a lot of creatinine in our body, we ARE expected to have some.

How do we evaluate it?

So, there are a couple ways to measure creatinine, however I’m going to focus on the big two: serum blood labs and creatinine clearance. 

Serum Creatinine 

For the average adult: 0.6-1.2 mg/dL

For serum creatinine, you follow all of your regular blood draw steps. Typically, this is collected in the red-top vacutainer. You’ll send this down to the lab and they’ll send your results to the patient chart or may even call the nurses station. 

Seeing a rise in your patient’s creatinine levels are usually associated with CHF, AGN or CGN, and Chronic Kidney Disease. The reason why is because when you have impaired functioning of the kidney, its not going to excrete wastes like it used to. See my CKD review for more help. :)

Seeing a fall in your patient’s creatinine is usually associated with a decline in muscle mass. This is seen a lot in muscle dystrophy.

Creatinine Clearance (CrCl)

For the average adult: 87-139 mL/min

So, the CrCl is collected with by 24-hour urine specimen. We want these patients collecting their urine, so remind them that after flushing the first urination of the morning, do not flush anymore of their urine. Show them where and how to collect their urine. If they are using a specipan, remind them that no toilet paper should go in the basin. We don’t want any tampering inside of the collection device. 

Seeing a rise in your CrCl could mean a couple things: pregnancy, high cardiac output, and possibly they’ve been exercising.

Kostantinova - finished 4th (5th, 2nd, no GPF).

Zagitova - finished 5h. (1st, 1st, 2nd in GPF).

Samodurova - finished 6th (3rd, 2nd, 5th at GPF).

Medvedeva - finished 7th (3rd, 4th, no GPF).

Tuktamysheva - didn’t compete (1st, 3rd, 3rd at GPF).