Urine electrolytes and the urine anion and osmolar gaps☆,☆☆
Section snippets
Group I
One hundred fifty-nine randomly voided urine samples were collected from non-fasting patients at the Medical College of Virginia renal disease clinic. The male-to-female ratio was 61 to 98. Most of the patients were being followed for chronic renal failure secondary to hypertension and/or diabetes. These samples were analyzed for Na+, K+, Cl–, creatinine, osmolality, and sulfate.
Group II
Thirty patients being seen in the renal clinic had routine blood chemistries performed as part of their regular
Results
The data from 159 randomly voided urine samples are shown in Table I.Parameter Mean SD Range 95% CL Na+ (mmol/L) 72.0 37.0 9.0/187.0 66.0/78.0 K+ (mmol/L) 28.0 19.0 3.0/147.0 25.0/31.0 Cl– (mmol/L) 96.0 50.0 12.0/257.0 88.0/104.0 SO4 2– (mmol/L) 8.5 5.1 0.6/33.0 7.8/9.3 SO4 2– (mmol/g creatinine) 9.7 4.5 0.5/21.0 9.0/10.4 Osmolality (mOsm/L) 434.0 144.0 134.0/1019.0 412.0/456.0 Na+ + K+ –Cl– (mEq/L) 3.7 30.0 –113.0/124.0 –0.9/8.3 Na++K+–Cl––SO4 2– (mEq/L) –13.0 30.0 –132.0/88.0 –18.0/–8.0
Discussion
Renal excretion of ammonium figures prominently in all discussions of the kidney's response to metabolic acidosis.1, 2, 3, 4 Therefore it is distressing that clinicians rarely have access to urinary ammonium levels that, at the very least, would be a useful measure of kidney function and might be diagnostic of the cause of the acidosis itself.9, 10, 11 Failure of the kidney to increase its output of ammonium in the setting of acidosis indicates that a defect in renal acidification may be
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