Department of Diagnostic Sciences, Ghent University Hospital, Ghent, Belgium.
Department of Nephrology, Ghent University Hospital, Ghent, Belgium.
Clin Chem Lab Med. 2023 Apr 24;61(8):1382-1387. doi: 10.1515/cclm-2023-0260. Print 2023 Jul 26.
Detection of hemoglobin (Hb) and red blood cells in urine (hematuria) is characterized by a large number of pitfalls. Clinicians and laboratory specialists must be aware of these pitfalls since they often lead to medical overconsumption or incorrect diagnosis. Pre-analytical issues (use of vacuum tubes or urine tubes containing preservatives) can affect test results. In routine clinical laboratories, hematuria can be assayed using either chemical (test strips) or particle-counting techniques. In cases of doubtful results, Munchausen syndrome or adulteration of the urine specimen should be excluded. Pigmenturia (caused by the presence of dyes, urinary metabolites such as porphyrins and homogentisic acid, and certain drugs in the urine) can be easily confused with hematuria. The peroxidase activity (test strip) can be positively affected by the presence of non-Hb peroxidases (e.g. myoglobin, semen peroxidases, bacterial, and vegetable peroxidases). Urinary pH, haptoglobin concentration, and urine osmolality may affect specific peroxidase activity. The implementation of expert systems may be helpful in detecting preanalytical and analytical errors in the assessment of hematuria. Correcting for dilution using osmolality, density, or conductivity may be useful for heavily concentrated or diluted urine samples.
尿液中血红蛋白（Hb）和红细胞（血尿）的检测存在许多陷阱。临床医生和实验室专家必须意识到这些陷阱，因为它们常常导致医疗过度或误诊。分析前问题（使用真空采血管或含有防腐剂的尿液管）会影响检测结果。在常规临床实验室中，可以使用化学（测试条）或颗粒计数技术来检测血尿。在结果可疑的情况下，应排除马方综合征或尿液标本掺假。色素尿（由染料、尿液代谢物如卟啉和对羟苯乙酸、以及尿液中的某些药物引起）容易与血尿混淆。过氧化物酶活性（测试条）可能会受到非 Hb 过氧化物酶的影响（如肌红蛋白、精液过氧化物酶、细菌和植物过氧化物酶）。尿液 pH 值、触珠蛋白浓度和尿液渗透压可能会影响特定的过氧化物酶活性。实施专家系统可能有助于检测血尿评估中的分析前和分析错误。使用渗透压、密度或电导率校正稀释可能对高度浓缩或稀释的尿液样本有用。
