title: Determination of blood cell subtype concentrations from frozen whole blood samples using TruCount beads.
abstract: In many studies it would be advantageous if blood samples could be collected and analyzed using flow cytometry at a later stage. Ideally, sample collection should involve little hands-on time, allow for long-term storage, and minimally influence the samples.
  
  
  
  Here we establish a flow cytometry antibody panel that can be used to determine granulocytes, monocytes, and lymphocyte subset concentrations in fresh and frozen whole blood using TruCount technology.
  
  
  
  The panel can be used on fresh whole-blood samples as well as whole-blood samples that have been frozen after mixing with 10% DMSO. Concentrations in frozen and fresh sample is highly correlated both when frozen within 4 h and the day after collection (r ≥ 0.98), and the estimated concentration in frozen samples was between 91 and 94% of that in fresh samples for all cell types.
  
  
  
  Using this method whole-blood samples can be frozen using a simple preparation method, and stored long-term before accurate determination of cell concentration. This allows for standardized analysis of the samples at a reference laboratory in multi-center studies. © 2016 International Clinical Cytometry Society.
authors.affiliation: Department of Pediatrics, Institute of Clinical Sciences, University of Gothenburg, Gothenburg, Sweden.|Queen Silvia Children's Hospital, Sahlgrenska University Hospital, Gothenburg, Sweden.
authors.forename: Cecilia
authors.initials: C
authors.lastname: Langenskiöld
authors.affiliation: Department of Pediatrics, Institute of Clinical Sciences, University of Gothenburg, Gothenburg, Sweden.|Queen Silvia Children's Hospital, Sahlgrenska University Hospital, Gothenburg, Sweden.
authors.forename: Karin
authors.initials: K
authors.lastname: Mellgren
authors.affiliation: Department of Pediatrics, Institute of Clinical Sciences, University of Gothenburg, Gothenburg, Sweden.|Queen Silvia Children's Hospital, Sahlgrenska University Hospital, Gothenburg, Sweden.
authors.forename: Jonas
authors.initials: J
authors.lastname: Abrahamsson
authors.affiliation: Department of Microbiology and Immunology, Institute of Biomedicine, University of Gothenburg, Gothenburg, Sweden.|Department of Clinical Immunology and Transfusion Medicine, Sahlgrenska University Hospital, Gothenburg, Sweden.
authors.forename: Mats
authors.initials: M
authors.lastname: Bemark
mesh_terms: D000328:Adult; D000368:Aged; D015925:Cryopreservation; D005260:Female; D005434:Flow Cytometry / Q000379:methods*; D006801:Humans; D016130:Immunophenotyping / Q000379:methods*; D007958:Leukocyte Count / Q000379:methods*; D008297:Male; D008875:Middle Aged; D013048:Specimen Handling; D055815:Young Adult
keywords: TruCount; absolute cell count; clinical trial; cryopreservation; flow cytometry; immunophenotyping; peripheral blood