P018 | Improving diagnostic standardization in myeloproliferative neoplasms: results from the Italian JakNet Program

Abstract

Introduction. The JAK2V617F mutation is the most common driver event in Myeloproliferative Neoplasms (MPNs), leading to cytokine-independent JAK/STAT activation and contributing to both disease onset and progression. Accurate quantification of the JAK2V617F variant allele frequency (VAF) is essential for diagnosis and monitoring. In 2018, GIMEMA established JakNet, a network of Italian hematology laboratories (labs) supported by Novartis, to promote methodological harmonization and standardize JAK2V617F testing through shared recommendations and annual quality controls (QC).
Methods. Since 2018, labs have undergone yearly QC rounds using the NIBSC 1st Panel JAK2V617F reference standards, comprising seven DNA samples with defined VAF (0–100%). Labs were defined as “compliant” when all the values were included in the acceptable intervals, “operationally non-compliant” when the discrepancies detected did not impact on the negative/positive classification, “non-compliant” if the discrepancies were in the crucial interval 0 to 1% interfering with the negative/positive definition. Analytical methods (HRMA, RT-qPCR, ddPCR) were compared over time.
Results. The network expanded from 35 lab in 2018–2019 to 50 in 2025, across Italy. Overall, a total of 54 labs participated: 22 in Northern Italy, 13 in Central Italy, and 19 in Southern Italy; 35 were university- and 19 hospital-based. Analytical performance improved: compliant labs rose from 74% in 2018 to 78% in 2024, peaking at 82% in 2023. Operationally non-compliant labs decreased from 20–31% to 5–11% in 2023–2024, while the proportion of non-compliant remained consistently low over years, usually below 15%, reflecting the overall robustness of laboratory performance. In 2025, compliance slightly dropped to 70% due to an increase in operationally non-compliant labs (22%), while non-compliant labs remained at 8%. Method adoption evolved: in 2018, 71% of labs used RT-qPCR, 26% ddPCR, and 3% HRMA; by 2020, HRMA was nearly phased out. Between 2022 and 2025, RT-qPCR remained predominant (70–76%) and ddPCR slightly increased (23–30%). The use of ddPCR and standardized CE-IVD kits ensured QC compliance, while semi-quantitative approaches showed variable accuracy (figure 1).
Between 2018 and 2025, of 13 labs initially considered as operationally non-compliant, 8 became fully compliant, 4 remained operationally non-compliant, and 1 became non-compliant. Of 5 labs initially non-compliant, 2 improved to full compliance, demonstrating the favorable impact of continuous QC and proficiency programs in fostering methodological standardization.
Conclusions. JakNet established a national framework for standardizing JAK2V617F testing in MPNs. Quantitative molecular methods and systematic QC improved assay accuracy and inter-laboratory consistency. Continued participation and data sharing strengthen diagnostic harmonization and support integration of innovative technologies in molecular hematology.