Accuracy of 24 hour urinalysis

[mychaelelaine]

Ok, so, I called today and was told my protein was 160. Last week it was 115 but I thought (and the Dr) that might be inaccurate because I didn't do it 100% accurately. It was 280 two weeks ago. Yes, I'm a ding bat. So, I asked if I could do it again. When I dropped it off Wednesday, the lab tech says "that's all?" I did it completely right this time... It was just a 1/4 to 1/3 full. Can the amount affect the accuracy?

[LBD30]

Maybe your urine output is decreasing? That happened to me at 34 wks and I had to deliver because of decreased kidney function. Or maybe you just did not drink enough?

[mychaelelaine]

Good points but my question is... will low urine output affect the accuracy of the results?

[caryn]

24 hours are calculated in mg alone, with no deciliters in the accounting. It's just how many milligrams in 24 hours.

[mychaelelaine]

24 hours are calculated in mg alone, with no deciliters in the accounting. It's just how many milligrams in 24 hours.

Ok caryn, I'm having a slow pregnancy moment. . . is that a yes or no? Lol. I'm certain your response is basically saying no, low urine output won't affect the accuracy of the results but just want to make sure. You got just a little too high tech for me this late in the day after work.

[caryn]

Hee, sorry - I was typing fast.

No, output might reflect oliguria, but will not affect what they're worried about when they calculate proteinuria over a 24 hour period. The funny thing is, English reflects that, but in a way that doesn't always make sense! They literally just want proteinuria over a 24 hour period, or

proteinuria
_____________ <--- see, it's actually over the 24 hours, when we write it in math notation! The fraction just works like that.

24 hours

or the total amount or proteinuria in the 24 hour catch. When I teach math, almost everyone has missed this! Math is so unintuitive.

[mychaelelaine]

Thanks caryn!

[Bmoremama]

I didnt know that! So on the urine dip sticks they do in the office, is that the same units, just mg, or is that a concentration, mg per unit of volume?

[mychaelelaine]

As far as I know, it's a concentration. I was quite shocked to find out the dipsticks aren't accurate. The way the triage dr explained, you urinate one time and there's protein. Next minute, you can urinate and there's a smaller amount of protein.

[caryn]

Right - the dipsticks are mg/dL. 30 mg/dL is a +1, 300 mg/dL is a +3, etc. And the number of deciliters can vary dramatically depending on how much you've had to drink lately, so you can end up with a +1 if your urine is quite concentrated.

Smaller output can tip over the diagnostic line into oliguria, especially if you're also swelling substantially. When my kidneys finally gave up I had pulmonary edema and needed an oxygen mask - just another of the indications that it was time to deliver, for me.