Three years of preanalytical errors: quality specifications and improvement through implementation of statistical process control

The objectives of this research were to show the most frequent preanalytical sample errors from two distinct patient populations and blood-drawing personnel, to calculate preanalytical quality specifications, and to demonstrate an improvement strategy for patients whose samples have been drawn in the primary health care center by means of a monthly preanalytical quality control report based on statistical process control (SPC).

We collected preanalytical errors from the tests requested for hematology, coagulation, chemistry, and urine samples in both populations. To monitor an improvement strategy, we designed a set of indicators. The indicator results for 35 months were entered into the statistical software application, where they were statistically analyzed. The preanalytical quality specifications were calculated using the SPC control charts. The intervention consisted of the sending of a monthly preanalytical quality report to a pilot Decentralized Phlebotomy Center (DPC) and setting up a direct communication channel between the laboratory and the DPC.

Fewer errors were observed when the sample drawing was carried out by the laboratory personnel, showing distinct preanalytical quality specifications. Improvements were seen in the DPC after four months of the improvement strategy.

We show a practical and effective methodology for the identification, monitoring, and reduction of preanalytical errors using the technology employed in daily total testing laboratory process.