Human immunodeficiency virus (HIV) pre-exposure prophylaxis (PrEP) encompasses the use of antiviral medications to prevent HIV acquisition in individuals without HIV who are at risk. Currently available HIV PrEP medications are nucleoside reverse transcriptase inhibitors and integrase inhibitors. HIV testing is required to confirm that patients do not have an HIV infection before PrEP, when restarting PrEP after a long pause, and during ongoing maintenance of PrEP. This article reviews current practices and recent developments in PrEP. Daily oral HIV PrEP is a common approach for HIV PrEP. The challenge with oral HIV PrEP is medication adherence. Recently, long-acting injectable medications for HIV PrEP have become available, which may improve adherence. HIV testing plays a critical role in PrEP programs. Methods for HIV testing for PrEP programs include laboratory-based antigen/antibody immunoassays, rapid testing with reflex confirmation, and RNA testing. The World Health Organization encourages the use of rapid HIV assays for self-testing because provider-administered testing may be a barrier to PrEP uptake. Currently available HIV self-testing (HIVST) methods are primarily antibody-based rapid assays. To improve the effectiveness of HIV PrEP, a greater range of medications, including novel long-acting antiretroviral agents, broadly neutralizing antibodies, and other drugs, are needed. Additionally, more accessible PrEP service delivery and high-sensitivity HIV tests, especially nucleic acid-based HIVST methods, are warranted. HIV PrEP and related monitoring are essential parts of HIV prevention. More effective medications will improve the effectiveness of HIV PrEP, and more accessible PrEP service delivery and high-sensitivity HIV tests, especially HIVST methods, can improve HIV prevention with PrEP.

The European Union (EU) In Vitro Diagnostic Regulation (IVDR) imposes stringent obligations on laboratories using in-house in vitro diagnostic devices (IH-IVDs), yet offers limited clarity on whether discrete work flow steps may be subcontracted while maintaining compliance with Article 5(5). This Special Report identifies 3 systemic challenges that amplify regulatory uncertainty: (a) fragmented national implementation of the IVDR, (b) disparities in the application of ISO 15189-based quality systems, and (c) the withdrawal of Conformité Européene (CE)-marked IVDs from the market, often replaced by research use only (RUO) products that shift the regulatory burden to public laboratories. These dynamics disproportionately affect diagnostics for rare diseases, emerging pathogens, and precision medicine, areas where commercial IVDs are often unavailable or withdrawn for cost reasons. Laboratories are increasingly compelled to adopt RUO products within IH-IVD work flows, accepting legal and clinical responsibility for analytical validity without clear regulatory protection. At the same time, innovation in academic and translational settings is hindered by uneven national oversight, premature enforcement of deferred IVDR clauses, and the absence of a harmonized European compliance model. We analyze these pressures through the lens of the respective Medical Device Coordination Group (MDCG) guidance, current national practices, and ISO 5649:2024-a newly published standard offering risk-based governance of IH-IVDs. ISO 5649 enables safe subcontracting under strict accountability and provides a structured compliance pathway aligned with the IVDR. Without urgent coordination across Member States and adoption of such frameworks, the EU risks undermining both patient access and diagnostic innovation under the banner of regulatory harmonization.

Circulating cell-free DNA (cfDNA) fragmentomic features, such as fragment size and end motifs, have emerged as promising noninvasive biomarkers for cancer detection. However, the influence of nonmalignant clinical factors on these features remains unclear, potentially confounding liquid biopsy assays. We analyzed cfDNA fragmentomic data from 1154 noncancerous individuals undergoing routine health checkups. Three cfDNA features were examined: cfDNA concentration, short fragment ratio (SFR), and cancer-enriched motif (CEM) frequency. Associations with 65 demographic, hematologic, and biochemical variables were assessed using univariate and multivariate analyses. High-resolution correlation mapping of fragment size (110 to 230 bp) and 4-mer end motifs was performed. Patterns were compared with profiles from 283 lung cancer patients, and confounding effects were evaluated using receiver operating characteristic (ROC) analysis. Multiple nonmalignant variables significantly correlated with cfDNA features. Age was associated with all three features, while liver function markers (aspartate aminotransferase [AST], alkaline phosphatase [ALP], γ-glutamyl transferase [γ-GTP]) showed strong associations with SFR and CEM frequency. High-resolution analyses revealed that AST-related fragment size profiles closely resembled cancer-associated patterns, whereas age showed partial similarity to cancer-associated end motif alterations. ROC analyses demonstrated that elevated AST or older age reduced the discriminative performance of SFR and CEM, indicating their potential as confounders in lung cancer detection. Physiological factors such as liver enzyme levels and age can significantly alter cfDNA fragmentomic profiles, generating patterns that resemble lung cancer-associated signals. These results highlight the importance of incorporating strategies to mitigate nonmalignant variability when developing cfDNA-based liquid biopsy assays, to ensure their accuracy, specificity, and clinical applicability.