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24 hour urine question

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24 hour urine question

Postby expert@preeclampsia.org » Mon Nov 05, 2007 12:25 am

by expert@preeclampsia.org (322 Posts), Mon Nov 05, 2007 12:25 am

My question is related to lab results that seem to be conflicting to me, and I do not understand the flucuation. I am in kind to believe that they are wrong, and I wondered if any clarification of them can be given to me. The are in reference to the PIH Panel and 24 hour urine tests.

My doctors have had me repeat the preeclamptic labs due to my history every 4 weeks up until week 29, now every week. I am now 31 weeks pregnant.

My baseline for the 24 hour urine was 68mg/24hrs

8/14 - Urine Creatinine 72.4, 24 hr Creat. Clearance 365.0, Urine Protein 7.0, 24 hour urine protein 126.00mg
9/21 - Urine Creatinine 79.2, 24 hr Creat. Clearance 100.6, Urine Protein <5.0, 24 hr urine protein (not listed)
9/27 - Urine Creatinine 81.0, Urine Protein 30.0, 24 hour urine protein 525.00mg (test repeated because OB felt 9/21 results were inaccurate.)
10/04- Urine Creatinine 68.6, 24 hr Creat. Clearance 100.5, Urine Protein 30.00, 24 hr urine protein 525.00mg
10/11 - Urine Creatinine 42.2, 24 hr Creat. Clearance 68.5, Urine Protein 6.0, 24 hr urine protein 105.00mg

Im no doctor or anything but it seems strange to me that particularly the 24 hour urine would change so radically in such a short time. Is it possible for it to read high one day, then a few days later be low again? And as far as other signs of a problem, how important is the urine creatinine and the 24 hour creat. Clearance. I just want to know from an expert opinion, do these lab values seem to wildly flucuate or are they fine and can vary as they have for me.

By the way my blood pressures have been fine. Earlier in my pregnancy they were low for me 110/60, now they are running average about 123/78 occassionally 126/84 but nothing higher than that. I have a history of preeclampsia, this is my third pregnancy I had preeclampsia with my first born at 33 weeks 3lb 10oz, and Severe PE/HELLP with my second born at 31 weeks at 2lbs. 11oz. With my second pregnancy I believe I had somewhere in the neighborhood of 7000+ grams of protein in my urine before I was delivered.

Any information/direction you can provide would be helpful.
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Re : 24 hour urine question

Postby expert@preeclampsia.org » Mon Nov 05, 2007 12:26 am

by expert@preeclampsia.org (322 Posts), Mon Nov 05, 2007 12:26 am

Of importance here is the blood pressure is still normal and with the increase from baseline, and your physicians checking labratories and I guess blood pressure on a weekly basis, it sounds like you are receiving close scrutiny from your care givers. Also the urinary protein excretion has been in the normal range with the exception of one that was of borderline significance.

There are many reason why proteinuria has fluctuated. First if they are based in a single urine protein/creatine ratio, it depends when during the day the specimen was obtained, early morning being the most reliable. This because the ratio theoretically assumes that protein excretion is constant throughout 24 hours, and this is probably not the case. Part of proteinuria is functional and can be influenced by posture, and activity, and other factors. If we are dealing with a 24 hour collection there are other problems, as 24 hour outpatients collections are difficult to achieve. Even if there are unintentional discards, the fact that the ureters normal dilate in pregnancy can lead to gross collection errors and what we call timing errors (urine produced an hour ago or more retained in the ureters at time of discard.) Since the dilated ureters normal for pregnancy can retain as much of 300 ml of urine, we have both over and undercollections. The current consensus is that the problems of single void Plasma /Creatinine ratios are less than those of a timed urine collection.

Finally, if the serum creatinine levels are steady, and within the normal for pregnancy range, the fluctuations in the GFR are also due to collection errors.
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