A prospective comparison of two endogenous creatinine clearance testing methods in hospitalized hypertensive gravid women.
OBJECTIVE
Although 24-hour endogenous creatinine clearance testing is common in pregnancies complicated by hypertension, inaccuracies limit its usefulness. We controlled the conditions under which 4-hour endogenous creatinine clearance testing was performed and compared the results with outcomes of 24-hour tests from the same patients.


METHODS
In 83 women hospitalized with mild hypertension in the third trimester, we measured endogenous creatinine clearance with a 4-hour urine collection during lateral recumbency and supervised oral hydration. This test was paired with a 24-hour test performed immediately thereafter. No restrictions or recommendations regarding ambulation or oral intake were imposed for the 24-hour test.


RESULTS
The 4-hour endogenous creatinine clearance value exceeded the 24-hour value in 133 of the 136 paired comparisons (p < 0.0001). Results of the tests from only the 29 patients with multiple paired tests showed more similarity (p < 0.005) among the 4-hour than among the 24-hour clearances.


CONCLUSIONS
The 4-hour endogenous creatinine clearance test, as described, provides a higher and less variable estimate of renal function in hypertensive pregnant women than does the 24-hour test.
Huddleston
J F
JF
Department of Obstetrics and Gynecology, University of Alabama at Birmingham.
Huggins
W F
WF
Williams
G S
GS
Flowers
C E
CE
D003404:Creatinine / Q000652:urine*; D004326:Drinking; D005260:Female; D006801:Humans; D006973:Hypertension / Q000378:metabolism*; D007668:Kidney / Q000378:metabolism; D009765:Obesity / Q000378:metabolism; D011187:Posture; D011247:Pregnancy; D011249:Pregnancy Complications, Cardiovascular / Q000378:metabolism*; D011263:Pregnancy Trimester, Third; D011446:Prospective Studies; D012044:Regression Analysis; D015203:Reproducibility of Results; D013997:Time Factors
D003404:Creatinine