de Scally M P, Leisewitz A L, Lobetti R G, Thompson P N
Bryanston Veterinary Hospital, South Africa.
J S Afr Vet Assoc. 2006 Dec;77(4):175-8. doi: 10.4102/jsava.v77i4.373.
Pigmented serum, usually due to free haemoglobin and/or bilirubin, is a common finding in dogs with babesiosis, resulting in interference with all biochemical tests that rely on photochemistry. This is particularly true of urea and creatinine determinations, complicating the diagnosis of acute renal failure, which is a serious complication of babesiosis. A disproportionately raised serum urea concentration of unknown origin occurs in severely anaemic canine babesiosis patients and gives rise to an increased serum urea:creatinine ratio. The assay for cystatin-C, an excellent measure of glomerular filtration rate, is unaffected by free serum haemoglobin, and due to its different intrinsic origins, is free of influence by the metabolic derangements and organ pathology, other than renal disease, encountered in canine babesiosis. Serum cystatin-C was used to compare the concentrations of serum urea and serum creatinine in dogs with the severely anaemic form of canine babesiosis as well as a canine babesiosis-free reference group. Mean serum urea and mean serum urea:creatinine ratio were significantly elevated in the babesia-infected group relative to the reference population in this study. Mean serum creatinine and mean serum cystatin-C were within the reference ranges. Therefore an elevated urea:creatinine ratio in canine babesiosis in the presence of a normal serum creatinine concentration is considered to be caused by an elevated serum urea concentration and is most likely of non-renal origin. Serum creatinine was therefore as specific a measure of renal function as serum cystatin-C in canine babesiosis in this study. The sensitivity of serum creatinine as a measure of renal function was not established by this study. Serum urea, however, proved to be of little use compared to serum cystatin-C and serum creatinine. Serum urea should therefore not be used to diagnose renal failure in canine babesiosis.
色素沉着血清通常由于游离血红蛋白和/或胆红素所致，在患巴贝斯虫病的犬中很常见，这会干扰所有依赖光化学的生化检测。尿素和肌酐测定尤其如此，这使得急性肾衰竭的诊断变得复杂，而急性肾衰竭是巴贝斯虫病的严重并发症。在重度贫血的犬巴贝斯虫病患者中，会出现不明原因的血清尿素浓度不成比例升高，导致血清尿素与肌酐比值增加。胱抑素-C检测是肾小球滤过率的一项出色指标，不受游离血清血红蛋白的影响，并且由于其内在来源不同，不受犬巴贝斯虫病中除肾脏疾病外所遇到的代谢紊乱和器官病理的影响。本研究使用血清胱抑素-C来比较重度贫血型犬巴贝斯虫病犬以及无巴贝斯虫病的犬参考组的血清尿素和血清肌酐浓度。在本研究中，相对于参考群体，巴贝斯虫感染组的平均血清尿素和平均血清尿素与肌酐比值显著升高。平均血清肌酐和平均血清胱抑素-C在参考范围内。因此，在血清肌酐浓度正常的情况下，犬巴贝斯虫病中尿素与肌酐比值升高被认为是由血清尿素浓度升高引起的，很可能是非肾源性的。因此，在本研究中，血清肌酐与血清胱抑素-C一样是犬巴贝斯虫病中肾功能的特异性指标。本研究未确定血清肌酐作为肾功能指标的敏感性。然而，与血清胱抑素-C和血清肌酐相比，血清尿素被证明用处不大。因此，血清尿素不应被用于诊断犬巴贝斯虫病中的肾衰竭。
