o:3264 Serum chemistry profiling and prognostication in systemic mastocytosis: a registry-based study of the ECNM and GREM en Certain laboratory abnormalities correlate with subvariants of systemic mastocytosis (SM) and are often prognostically relevant. To assess the diagnostic and prognostic value of individual serum chemistry parameters in SM, 2607 patients enrolled within the European Competence Network on Mastocytosis and 575 patients enrolled within the German Registry on Eosinophils and Mast Cells were analyzed. For screening and diagnosis of SM, tryptase was identified as the most specific serum parameter. For differentiation between indolent and advanced SM (AdvSM), the following serum parameters were most relevant: tryptase, alkaline phosphatase, β2-microglobulin, lactate dehydrogenase (LDH), albumin, vitamin B12, and C-reactive protein (P < .001). With regard to subvariants of AdvSM, an elevated LDH of ≥260 U/L was associated with multilineage expansion (leukocytosis, r = 0.37, P < .001; monocytosis, r = 0.26, P < .001) and the presence of an associated myeloid neoplasm (P < .001), whereas tryptase levels were highest in mast cell leukemia (MCL) vs non-MCL (308μg/L vs 146μg/L, P = .003). Based on multivariable analysis, the hazard-risk weighted assignment of 1 point to LDH (hazard ratio [HR], 2.1; 95% confidence interval [CI], 1.1-4.0; P = .018) and 1.5 points each to β2-microglobulin (HR, 2.7; 95% CI, 1.4-5.4; P = .004) and albumin (HR, 3.3; 95% CI, 1.7-6.5; P = .001) delineated a highly predictive 3-tier risk classification system (0 points, 8.1 years vs 1 point, 2.5 years; ≥1.5 points, 1.7 years; P < .001). Moreover, serum chemistry parameters enabled further stratification of patients classified as having an International Prognostic Scoring System for Mastocytosis-AdvSM1/2 risk score (P = .027). In conclusion, serum chemistry profiling is a crucial tool in the clinical practice supporting diagnosis and prognostication of SM and its subvariants. Humans; Mastocytosis, Systemicdiagnosisblood; Prognosis; Registries; Male; Female; Middle Aged; Adult; Aged; Biomarkersblood; Tryptasesblood 1552099 10.1182/bloodadvances.2024012756 2024-07-18T08:42:15.039Z 44 yes 46 Johannes Lübke Heidelberg University 0000-0003-0767-1504 Juliana Schwaab Heidelberg University person Andreas Reiter Heidelberg University person Peter Valent Medical University of Vienna person 0000-0003-0456-5095 Wolfgang R. Sperr Medical University of Vienna person Jens Panse RWTH Aachen University / Center for Integrated Oncology person 0000-0001-6316-3112 Hanneke C. Kluin-Nelemans University of Groningen person 0000-0003-2617-9427 Michel Arock University Paris person Olivier Hermine University Paris person Jason Gotlib Stanford University person Massimo Triggiani University of Salerno, person 0000-0001-7318-2093 Karin Hartmann University of Basel person 0000-0002-4595-8226 Tanja Schug University Hospital Graz person Vito Sabato University of Antwerp person Michael Doubek Masaryk University person Akif Selim Yavuz University of Istanbul person Toon Leven University Hospitals Leuven person Christine Breynaert University Hospitals Leuven person 0000-0002-7368-1068 Alexander Zink Technical University of Munich person 0000-0001-9313-6588 Knut Brockow Technical University of Munich person 0000-0002-2775-3681 Francesca Caroppo University of Padova person 0000-0003-3583-0816 Anna Belloni Fortina University of Padova person Judit Varkonyi Varkonyi person Roberta Parente University of Salerno person Mattias Mattsson Uppsala University person Hans Hagglund Uppsala University person Luca Malcovati Fondazione I.R.C.C.S. Policlinico San Matteo person 0000-0002-1460-1611 Chiara Elena Fondazione I.R.C.C.S. Policlinico San Matteo person Cecelia Perkins Stanford University person Sabine Müller University of Freiburg person Nikolas von Bubnoff University of Freiburg / German Cancer Consortium person Khalid Shoumariyeh University of Freiburg / German Cancer Consortium person Patrizia Bonadonna Verona University Hospital person Massimiliano Bonifacio Verona University Hospital person Roberta Zanotti Verona University Hospital person Irena Angelova-Fischer Johannes Kepler University person Alex Stefan Johannes Kepler University person Emir Hadzijusufovic University of Veterinary Medicine Vienna / Medical University of Vienna person 0000-0001-7409-4204 Karoline V. Karoline V Medical University of Vienna person Magdalena Lange Medical University of Gdańsk person 0000-0002-6967-1393 Aleksandra Gorska Medical University of Gdańsk person Marek Niedoszytko Medical University of Gdańsk person Alicia Schmid Heidelberg University person Deborah Christen RWTH Aachen University / Center for Integrated Oncology person 0000-0003-2839-5983 Hanneke N. G. Oude Elberink University of Groningen person 0000-0003-2844-2196 Lambert F. R. Span University of Groningen person application/pdf 1770938 https://phaidra.vetmeduni.ac.at/o:3264 no yes 18 70 1552253 Blood Advances 11 8 11 2890 2900 Elsevier 2024