Abstract
Specific gravity was measured with a strip test (N-Labstix SG, Ames Division, Miles, Puteaux, France) in 98 urine specimens obtained from 57 newborn infants; osmolality was measured with an osmometer. The strip test did not accurately predict urine osmolalities; a very weak correlation was found between the specific gravity and the osmolality (r 2=0.598,P<0.01). Specific gravity values up to 1.015 always indicated hypotonic urine with osmolality less than 211 mosmol/kg H2O, whereas higher values could be associated with either hypotonic or hypertonic urine. Therefore, the strip test cannot be recommended in the neonatal period because its clinical usefulness is strictly restricted to urine samples with low specific gravities (≤1.015) and without confounding variables (urine pH≥6.5, glucosuria, proteinuria, haematuria).
References
Benitez OA, Benitez, M, Stijnen T, Boot W, Berger HM (1986) Inaccuracy in neonatal measurement of urine concentration with a refractometer. J Pediatr 108:613–616
Lorenz JM, Kleinmann LI, Kotagal UR, Reller MD (1982) Water balance in very-low-birth-weight infants: relationship to water and sodium intake and effect on outcome. J Pediatr 101:423–432
Assadi FK, Fornell L (1986) Estimation of urine specific gravity in neonates with a reagent strip. J Pediatr 108:995–996
McCrossin T, Roy LP (1985) Comparison of hydrometry, refractometry, osmometry and Ames N-Multistix SG in estimation of urinary concentration. Aust Paediatr J 21:185–188
Kirschbaum BB (1983) Evaluation of a colorimetric reagent strip assay for urine specific gravity. Am J Clin Pathol 79:722
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Gouyon, J.B., Houchan, N. Assessment of urine specific gravity by reagent strip test in newborn infants. Pediatr Nephrol 7, 77–78 (1993). https://doi.org/10.1007/BF00861579
Received:
Revised:
Accepted:
Issue Date:
DOI: https://doi.org/10.1007/BF00861579