Guerra Ruiz Armando Raúl, Crespo Javier, López Martínez Rosa Maria, Iruzubieta Paula, Casals Mercadal Gregori, Lalana Garcés Marta, Lavin Bernardo, Morales Ruiz Manuel
Service of Clinical Biochemistry, Marqués de Valdecilla University Hospital, Santander, Spain.
Commission on Biochemistry of Liver Disease, SEQCML, Barcelona, Spain.
Adv Lab Med. 2021 Jul 9;2(3):352-372. doi: 10.1515/almed-2021-0047. eCollection 2021 Aug.
Elevated plasma bilirubin levels are a frequent clinical finding. It can be secondary to alterations in any stage of its metabolism: (a) excess bilirubin production (i.e., pathologic hemolysis); (b) impaired liver uptake, with elevation of indirect bilirubin; (c) impaired conjugation, prompted by a defect in the UDP-glucuronosyltransferase; and (d) bile clearance defect, with elevation of direct bilirubin secondary to defects in clearance proteins, or inability of the bile to reach the small bowel through bile ducts. A liver lesion of any cause reduces hepatocyte cell number and may impair the uptake of indirect bilirubin from plasma and diminish direct bilirubin transport and clearance through the bile ducts. Various analytical methods are currently available for measuring bilirubin and its metabolites in serum, urine and feces. Serum bilirubin is determined by (1) diazo transfer reaction, currently, the gold-standard; (2) high-performance liquid chromatography (HPLC); (3) oxidative, enzymatic, and chemical methods; (4) direct spectrophotometry; and (5) transcutaneous methods. Although bilirubin is a well-established marker of liver function, it does not always identify a lesion in this organ. Therefore, for accurate diagnosis, alterations in bilirubin concentrations should be assessed in relation to patient anamnesis, the degree of the alteration, and the pattern of concurrent biochemical alterations.
血浆胆红素水平升高是常见的临床现象。它可能继发于其代谢任何阶段的改变：(a)胆红素生成过多（即病理性溶血）；(b)肝脏摄取受损，间接胆红素升高；(c)结合受损，由尿苷二磷酸葡萄糖醛酸基转移酶缺陷引起；(d)胆汁清除缺陷，由于清除蛋白缺陷导致直接胆红素升高，或胆汁无法通过胆管到达小肠。任何原因引起的肝脏病变都会减少肝细胞数量，并可能损害血浆中间接胆红素的摄取，减少直接胆红素通过胆管的转运和清除。目前有多种分析方法可用于测定血清、尿液和粪便中的胆红素及其代谢产物。血清胆红素通过以下方法测定：(1)重氮转移反应，目前是金标准；(2)高效液相色谱法(HPLC)；(3)氧化、酶促和化学方法；(4)直接分光光度法；(5)经皮方法。尽管胆红素是一种公认的肝功能标志物，但它并不总能识别该器官的病变。因此，为了准确诊断，应结合患者病史、改变程度以及同时存在的生化改变模式来评估胆红素浓度的变化。
