Implementation of a new storage solution in a busy virology laboratory

In microbiology at The Royal Wolverhampton NHS Trust, serum samples are required to be stored by the department at –20°C for up to two years following processing for serological investigation.  An aliquot is taken from the primary blood tube for storage following the completion of testing.

Owing to the large number of samples being processed, the blood sciences track system has been used, as the historical method of manually pipetting samples became impractical. However, the aliquot function on the track system has proved very unreliable, with 23 recorded errors/breakdowns between February and November 2018. There is no back-up provision for the track-based system, meaning that reverting to manual processing of samples has been a regular occurrence, which is an extremely inefficient use of resources and introduces the possibility of human error.

Previously, sample aliquots were stored in 5 cm test tubes. Routine samples were stored in 46x19 cm racks of 216 samples. This allowed 648 samples to be stored on a single shelf within a freezer. For samples in storage from the current and preceding months, location in a particular rack was recorded in the sample file on the laboratory information management system (LIMS), stating the month, rack number and coordinates of the sample (eg May18 2/A1). Samples requiring two- year storage were placed directly into bags and stored in the freezer. One bag was used for each week, labelled with the month, year and week of storage.