External quality assessment (EQA) schemes are a tool for clinical laboratories to evaluate and manage the quality of laboratory practice with the support of an independent party (i.e., an EQA provider). Depending on the context, there are different types of EQA schemes available, as well as various EQA providers, each with its own field of expertise. In this review, an overview of the general requirements for EQA schemes and EQA providers based on international guidelines is provided. The clinical and scientific value of these kinds of schemes for clinical laboratories, clinicians and patients are highlighted, in addition to the support EQA can provide to other types of laboratories, e.g., laboratories affiliated to biotech companies. Finally, recent developments and challenges in laboratory medicine and quality management, for example, the introduction of artificial intelligence in the laboratory and the shift to a more individual-approach instead of a laboratory-focused approach, are discussed. EQA schemes should represent current laboratory practice as much as possible, which poses the need for EQA providers to introduce latest laboratory innovations in their schemes and to apply up-to-date guidelines. By incorporating these state-of-the-art techniques, EQA aims to contribute to continuous learning.

Patients with advanced triple-negative breast cancer (TNBC) benefit from treatment with atezolizumab, provided that the tumor contains ≥1% of PD-L1/SP142-positive immune cells. Numbers of tumor-infiltrating lymphocytes (TILs) vary strongly according to the anatomic localization of TNBC metastases. We investigated inter-pathologist agreement in the assessment of PD-L1/SP142 immunohistochemistry and TILs. Ten pathologists evaluated PD-L1/SP142 expression in a proficiency test comprising 28 primary TNBCs, as well as PD-L1/SP142 expression and levels of TILs in 49 distant TNBC metastases with various localizations. Interobserver agreement for PD-L1 status (positive vs. negative) was high in the proficiency test: the corresponding scores as percentages showed good agreement with the consensus diagnosis. In TNBC metastases, there was substantial variability in PD-L1 status at the individual patient level. For one in five patients, the chance of treatment was essentially random, with half of the pathologists designating them as positive and half negative. Assessment of PD-L1/SP142 and TILs as percentages in TNBC metastases showed poor and moderate agreement, respectively. Additional training for metastatic TNBC is required to enhance interobserver agreement. Such training, focusing on metastatic specimens, seems worthwhile, since the same pathologists obtained high percentages of concordance (ranging from 93% to 100%) on the PD-L1 status of primary TNBCs.

Increasing data suggests that an intact immune system is required for improved outcomes in patients with Human Epidermal Growth Factor Receptor 2 (HER2+) and Triple Negative Breast Cancer (TNBC)

Cystic fibrosis (CF) is caused by variants in the cystic fibrosis transmembrane conductance regulator (CFTR) gene inherited by both parents. Revolutionary CFTR modulator therapy has improved the quality of life of patients living with CF in recent years. Drug eligibility is mainly based on the patient’s genotype, stressing the importance of genetic analysis. During this retrospective study on CF external quality assessment (EQA) data over three scheme years, we analyzed reporting approaches by genetics laboratories regarding modulator eligibility. We looked at 496 laboratory reports in total (181 reports in 2018; 158 in 2020;157 in 2022). The majority of laboratories correctly addressed genotype’s eligibility. Nonetheless, we observed a lot of variation between laboratories in the way how they reported on this issue. There was no statistically significant effect of sample volume, previous EQA experience, accreditation status, laboratory setting nor if the laboratory was familiar with testing of patients’ samples on performance. Some laboratories refused to comment on therapy options since it was not considered the responsibility of the laboratory. Nevertheless, since the genotype plays a key role in addressing CFTR modulator eligibility, early reporting on drug eligibility by the laboratory could potentially decrease time-to-treatment.