Role of training activities for the reduction of pre-analytical errors in laboratory samples from primary care

The presence of pre-analytical errors (PE) is a usual contingency in laboratories. The incidence may increase where it is difficult to control that period, as it is the case with samples sent from primary care (PC) to clinical reference laboratory. Detection of a large number of PE in PC samples in our Institution led to the development and implementation of preventive strategies. The first of these has been the realization of a cycle of educational sessions for PC nurses, followed by the evaluation of their impact on PE number.

The incidence of PE was assessed in two periods, before (October-November 2007) and after (October-November, 2009) the implementation of educational sessions. Eleven PC centers in the urban area and 17 in the rural area participated. In the urban area, samples were withdrawn by any PC nurse; in the rural area, samples were obtained by the patient's reference nurse. The types of analyzed PE included missed sample (MS), hemolyzed sample (HS), coagulated sample (CS), incorrect sample (ISV) and others (OPE), such as lipemic or icteric serum or plasma.

In the former period, we received 52,669 blood samples and 18,852 urine samples, detecting 3885 (7.5%) and 1567 (8.3%) PEs, respectively. After the educational intervention, there were 52,659 and 19,048 samples with 5057 (9.6%) and 1.256 (6.5%) PEs, respectively (p<0.001). According to the type of PE, the incidents compared before and after compared incidences were: MS, 4.8% vs. 3.8%, p<0.001; HS, 1.97% vs. 3.9%, p<0.001; CS, 0.54% vs. 0.25%, p<0.001; ISV, 0.15% vs. 0.19% p=0.08; and OPE, 0.3% vs. 0.42%, p<0.001.

Surprisingly the PE incidence increased after the educational intervention, although it should be noted that it was primarily due to the increase of HS, as the other EP incidence decreased (MS and CS) or remained unchanged (ISV). This seems to indicate the need for a comprehensive approach to reduce the incidence of errors in the pre-analytical period, as one stage interventions do not seem to be effective enough.