Local quality assurance of serum or plasma (HIL) indices

The presence of hemolysis (H), icterus (I) and lipaemia (L) in serum or plasma samples may be regarded as an important preanalytical drawback, since an abnormal concentration of these substances may derange the global quality and reliability of the total testing process. Although the assessment of sample quality before testing by means of the so-called HIL indices has become an essential part of routine practice in most clinical laboratories worldwide, no clear indications have been provided about the quality assurance of these measures. This article is hence aimed to provide an expert opinion about management of internal quality control (IQC) assessment for HIL indices. In summary, we support the use of in-house prepared IQC materials with at least two different levels for each interfering substances. IQC testing should be performed for validating performance of HIL indices in routine and urgent conditions, at least 2 times per day, and systematically recorded. We also suggest that results may be unacceptable when a single value of IQC material exceeds the mean target value by ±3 standard deviations. When results do not meet their set performance goals, the ensuing procedure mirrors that of conventional laboratory IQC management.