## 3 Results
### Pre- and Post-TLA Cost Analysis  
The cost per serology test type (HIV and COVT-COVIDGG) was estimated in pre- and post-TLA scenarios, including the following cost items: reagents, instrumentation, equipment and direct labour costs. Indirect laboratory costs and other consumable costs were not considered in the calculation because no major changes were applied with the TLA. An average improvement ratio (pre- to post-TLA) was also calculated and the estimated savings per year after the TLA implementation were assessed.  
The pre-TLA analysis was handled in 2020 (annual volume of 226,615 tests), and post-TLA analysis was performed in 2022 with the full laboratory automation implementation (annual volume of 210,315 tests). Partial automation and equipment replacement started in April 2021, and the change was completed in September 2021. The COVT and COVIDIGG serology testing started in March 2020. Because of the pandemic situation, the laboratory suffered a peak sample volume that stressed the laboratory personnel, routines and equipment, generating a bottleneck that was managed with additional working shifts to gain testing and diagnosis capacity. Neither laboratory automation nor specific algorithms existed at that moment.  
Table 4 shows the cost comparison in the pre- and post-TLA workflows for HIV and COVT-COVIDGG testing, showing an improvement ratio of 10.6% for HIV (EUR 0.43/test) and 1.4% for the second group of tests (EUR 0.14/test). The improvement of the process workflow minimised multiple sample transports and manual manipulations, influencing the direct labour costs per test. The equipment changes explained in Section 2.3 with the automation affected the equipment and reagent costs per test. In the case of COVT-COVIDGG testing, the cost reduction does not consider the impact of equipment and reagents costs because no data were available for the pre-TLA scenario in 2020. The immunoassay testing systems used in the pre-TLA scenario did not change, but a reduction in the direct labour costs of 7.1% was assessed due to the improved workflow and task redefinition. The estimated annual cost savings are EUR 15,212.22, considering 29,216 HIV tests and 18,273 COVT-COVIDGG tests performed in 2022.  
Regarding main process KPIs in pre-TLA and post-TLA scenarios, the total labour cost per day was calculated by considering the direct labour time invested on each test by technicians and doctor. The percentage share of each test among the total, representing HIV (13.9%) and COVT-COVIDGG (8.7%), has weighted fulltime equivalent (FTE). The reduction in the labour necessities (40%) supposes an improvement in terms of labour cost for HIV and COVT-COVIDGG testing.  
If results are evaluated for the whole-laboratory pre- and post-TLA scenarios, they show additional results concerning productivity considered as production rate of conforming serology tests per FTE, which is now equivalent to the laboratory staff number in view of their category of fulltime employees. Table 4 also shows productivity differentiation between processing and validation phases. The FTE number was reduced from five people in pre-TLA to three in post-TLA, removing one laboratory technician in the serology area that was assigned to other functions and one clinician. The average daily productivity of the laboratory increased from 171 to 284 tests/FTE, which meant an average improvement ratio of 65.9%. Personnel costs decreased with the removal of one clinician and one technician by EUR 70,841.24 per year, corresponding to the gross salaries per year in view of the category.