Herein we describe the genetic diversity of circulating SARS-CoV-2 viruses by whole-genome sequencing (WGS) in Barcelona city (Catalonia, Spain) throughout the first four pandemic waves. From weeks 11/2020 to 24/2021, SARS-CoV-2-positive respiratory samples were randomly selected per clinical setting (80% from primary care or 20% from hospital), age group, and week. WGS was performed following the ARTICv3 protocol on MiSeq or NextSeq2000 Illumina platforms. Nearly complete consensus sequences were used for genetic characterisation based on GISAID and PANGOLIN nomenclatures. From 2,475 samples, 2,166 (87%) were fully sequenced (78% from primary care and 22% from hospital settings). Multiple genetic lineages were co-circulating, but four were predominant at different periods. While B.1.5 (50.68%) and B.1.1 (32.88%) were the major lineages during the first pandemic wave, B.1.177 (66.85%) and B.1.1.7 (83.80%) were predominant during the second, third and fourth waves, respectively. Almost all (96.4%) were carrying D614G mutation in the S protein, with additional mutations that define lineages or variants. But some mutations of concern, such as E484 K from B.1.351 and P.1 lineages are currently under monitoring, together with those observed in the receptor binding domain or N-terminal domain, such as L452R and T478 K from B.1.617.2 lineage. The fact that a predominant lineage was observed in each pandemic wave, suggests advantageous properties over other contemporary co-circulating variants. This genetic variability should be monitored, especially when massive vaccination campaign is ongoing because the potential selection and emergence of novel antigenic SARS-CoV-2 strains related to immunological escapement events.

Background: Alpha-1 antitrypsin deficiency (AATD) remains largely underdiagnosed despite recommendations of healthcare institutions and programmes designed to increase awareness. The objective was to analyse the trends in AATD diagnosis during the last 5 years in a Spanish AATD reference laboratory. Methods: This was a retrospective revision of all alpha-1 antitrypsin (AAT) determinations undertaken in our laboratory from 2015 to 2019. We analysed the number of AAT determinations performed and described the characteristics of the individuals tested, as well as the medical specialties and the reasons for requesting AAT determination. Results: A total of 3507 determinations were performed, of which 5.5% corresponded to children. A significant increase in the number of AAT determinations was observed from 349 in 2015 to 872 in 2019. Among the samples, 57.6% carried an intermediate AATD (50– 119 mg/dL) and 2.4% severe deficiency (< 50 mg/dL). The most frequent phenotype in severe AATD individuals was PI*ZZ (78.5%), and aminotransferase levels were above normal in around 43% of children and 30% of adults. Respiratory specialists requested the highest number of AAT determinations (31.5%) followed by digestive diseases and internal medicine (27.5%) and primary care physicians (19.7%). The main reason for AAT determination in severe AATD adults was chronic obstructive pulmonary disease (41.7%), but reasons for requesting AAT determination were not reported in up to 41.7% of adults and 58.3% of children. Conclusion: There is an increase in the frequency of AATD testing despite the rate of AAT determination remaining low. Awareness about AAT is probably increasing, but the reason for testing is not always clear.

Objectives: The establishment of reference intervals (RIs) for biochemical parameters is crucial for the accurate interpretation of laboratory test results and clinical decision-making. This study aims to evaluate the feasibility of determining RIs using an indirect approach, which analyzes routine clinical samples instead of recruiting healthy individuals, thus leveraging large datasets while applying strict statistical criteria to exclude pathological values. Methods: This is a prospective study in which patients fulfilling inclusion criteria were recruited from the routine primary care to achieve a high proportion of healthy individuals. Biochemical magnitudes as creatinine, esterified bilirubin, ferritin, and transferrin were analyzed. A patient exclusion protocol was implemented to minimize results suggestive of pathology but ensuring a sufficient sample size for the calculation of new RIs. The new ones were compared with the RIs used in the laboratory, provided by the manufacturer. Results: The comparison between the newly calculated RIs and the existing laboratory RIs did not reveal statistically significant differences. The indirect approach provided robust RIs while maintaining data quality and a sufficient sample size. Conclusions: The findings support the effectiveness of this indirect approach for RI determination, provided that rigorous data quality standards and adequate sample sizes are maintained. The adoption of these RIs in clinical practice could enhance diagnostic accuracy and optimize healthcare resource utilization.

Background: Emergency Department (ED) viral hepatitis screening programs typically report short-term outcomes. We evaluated the medium-term impact of an ED-based screening for Hepatitis C (HCV), Hepatitis B (HBV), and Hepatitis D (HDV) viruses. Methods: Prospective opportunistic screening conducted between January 2020 and December 2024 at a referral hospital in Barcelona. Adults attending the ED were screened for HBV, HCV, and HDV. Positive cases were evaluated and linked to care when appropriate. To assess screening impact, HCV RNA and HBsAg prevalences were compared between 2020–2021 and 2023–2024 among participants aged ≤80 years. Results: Over five years, 39,532 individuals were screened: 220 (0.56%) had detectable HCV RNA, 234 (0.59%) HBsAg, and 4 HDV RNA. Of 110 patients with detectable HCV RNA eligible for linkage, 84 (76%) were treated and cured. Among 135 HBV-positive individuals eligible for linkage, 116 (86%) attended outpatient follow-up. HCV RNA prevalence significantly decreased (0.58% vs. 0.35%, p = 0.005), whereas HBsAg prevalence did not vary (0.7% vs. 0.58%, p = 0.224). Conclusions: Sustained ED-based screening enabled the identification and linkage to care of several individuals with HBV and HCV. This strategy contributed to a reduction in HCV prevalence among ED attendees and supports opportunistic ED screening in viral hepatitis elimination goals.