Lippi Giuseppe, Salvagno Gian Luca, Montagnana Martina, Brocco Giorgio, Guidi Gian Cesare
Istituto di Chimica e Microscopia Clinica, Dipartimento di Scienze Morfologico-Biomediche, Università degli Studi di Verona, Verona, Italy.
Clin Chem Lab Med. 2006;44(3):311-6. doi: 10.1515/CCLM.2006.054.
Preanalytical factors are the main source of variation in clinical chemistry testing and among the major determinants of preanalytical variability, sample hemolysis can exert a strong influence on result reliability. Hemolytic samples are a rather common and unfavorable occurrence in laboratory practice, as they are often considered unsuitable for routine testing due to biological and analytical interference. However, definitive indications on the analytical and clinical management of hemolyzed specimens are currently lacking. Therefore, the present investigation evaluated the influence of in vitro blood cell lysis on routine clinical chemistry testing.
Nine aliquots, prepared by serial dilutions of homologous hemolyzed samples collected from 12 different subjects and containing a final concentration of serum hemoglobin ranging from 0 to 20.6 g/L, were tested for the most common clinical chemistry analytes. Lysis was achieved by subjecting whole blood to an overnight freeze-thaw cycle.
Hemolysis interference appeared to be approximately linearly dependent on the final concentration of blood-cell lysate in the specimen. This generated a consistent trend towards overestimation of alanine aminotransferase (ALT), aspartate aminotransferase (AST), creatinine, creatine kinase (CK), iron, lactate dehydrogenase (LDH), lipase, magnesium, phosphorus, potassium and urea, whereas mean values of albumin, alkaline phosphatase (ALP), chloride, gamma-glutamyltransferase (GGT), glucose and sodium were substantially decreased. Clinically meaningful variations of AST, chloride, LDH, potassium and sodium were observed in specimens displaying mild or almost undetectable hemolysis by visual inspection (serum hemoglobin < 0.6 g/L). The rather heterogeneous and unpredictable response to hemolysis observed for several parameters prevented the adoption of reliable statistic corrective measures for results on the basis of the degree of hemolysis.
If hemolysis and blood cell lysis result from an in vitro cause, we suggest that the most convenient corrective solution might be quantification of free hemoglobin, alerting the clinicians and sample recollection.
分析前因素是临床化学检测中变异的主要来源，在分析前变异的主要决定因素中，样本溶血会对结果可靠性产生重大影响。溶血样本在实验室实践中是相当常见且不利的情况，因为由于生物学和分析干扰，它们通常被认为不适合常规检测。然而，目前缺乏关于溶血标本分析和临床处理的确切指导。因此，本研究评估了体外血细胞裂解对常规临床化学检测的影响。
通过对从12名不同受试者收集的同源溶血样本进行系列稀释制备9份等分试样，其血清血红蛋白终浓度范围为0至20.6 g/L，对最常见的临床化学分析物进行检测。通过使全血经历过夜冻融循环来实现裂解。
溶血干扰似乎大致线性依赖于标本中血细胞裂解物的终浓度。这导致丙氨酸氨基转移酶（ALT）、天冬氨酸氨基转移酶（AST）、肌酐、肌酸激酶（CK）、铁、乳酸脱氢酶（LDH）、脂肪酶、镁、磷、钾和尿素有一致的高估趋势，而白蛋白、碱性磷酸酶（ALP）、氯、γ-谷氨酰转移酶（GGT）、葡萄糖和钠的平均值则大幅下降。在通过目视检查显示轻度或几乎不可检测到溶血（血清血红蛋白<0.6 g/L）的标本中观察到AST、氯、LDH、钾和钠具有临床意义的变化。几个参数对溶血的反应相当异质且不可预测，这使得无法根据溶血程度对结果采取可靠的统计校正措施。
如果溶血和血细胞裂解是由体外原因引起的，我们建议最方便的校正解决方案可能是定量游离血红蛋白，提醒临床医生并重新采集样本。
