View source for Isosthenuria

'''Isosthenuria''' refers to the excretion of urine whose [[specific gravity (kidney)|specific gravity]] (concentration) is neither greater (more concentrated) nor less (more diluted) than that of protein-free [[blood plasma|plasma]], typically 1.008-1.012.<ref>{{DorlandsDict|four/000055251|isosthenuria}}</ref> Isosthenuria reflects damage to the kidney's tubules or the [[renal medulla]].

A closely related term is '''hyposthenuria''', where the urine has a relatively low specific gravity "due to inability of the kidney to concentrate the urine normally".<ref>{{DorlandsDict|four/000051848|hyposthenuria}}</ref><ref>{{cite web |title=Medical Definition of HYPOSTHENURIA |url=https://www.merriam-webster.com/medical/hyposthenuria |publisher=[[Merriam-Webster]] |access-date=2 February 2022 |language=English}}</ref> This specific gravity is not necessarily equal to that of plasma. Therefore, unlike isosthenuria, this condition is not associated with [[kidney failure]] as the kidney tubules have altered the [[Glomerulus|glomerular filtrate]].

==Clinical significance==
Isosthenuria may be seen in disease states as [[chronic kidney disease]] and [[acute kidney injury]] in which the [[kidneys]] lack the ability to concentrate or dilute the [[urine]] and so the initial filtrate of the blood remains unchanged despite the need to conserve or excrete water based on the body's hydration status.<ref>De Mais, Daniel. ASCP Quick Compendium of Clinical Pathology, 2nd Ed.  ASCP Press, Chicago, 2009.</ref>

[[Sickle-cell trait]], the heterozygous form of [[sickle-cell disease]], presents with a normal hematological picture but is associated with hyposthenuria.<ref>Gupta AK, Kirchner KA, Nicholson R, ''et al.'' Effects of alpha-thalassemia and sickle polymerization tendency on the urine-concentrating defect of individuals with sickle cell trait and increased frequency of [[urinary tract infection]]s J. Clin. Invest. Vol 88, Issue 6, pgs 1963-8.  Dec 1991. {{PMID|1752955}} PMC = 295777.  DOI = 10.1172/JCI115521</ref>

==See also==
* [[Hypersthenuria]]

==References==
{{Reflist}}

{{Abnormal clinical and laboratory findings for urine}}

[[Category:Abnormal clinical and laboratory findings for urine]]


{{Med-sign-stub}}