Analysis by Clinical Mass Spectrometry of Bloodstains
Condition: Patient Blood Biobank
Study type: Observational

Summary: 
      Dried Blood Spot or DBS is a collection of blood capillary drops spotted and dried on to a
      filter paper used for different bioanalysis. In comparison to conventional blood testing, DBS
      offers practical, analytical, clinical and financial advantages. This less invasive sampling
      is already used in infectious diseases screening and is useful for persons with poor venous
      (babies, drug users or elderly). Mass-spectrometry-based analyses allow protein
      quantification on very low amount of blood sample. In the project we combine the two
      approaches to measure on DBS blood proteins with clinical relevance -including many FDA
      approves biomarkers). The detection of the relevant clinical analytes will be validated on
      available patient samples in accordance with the clinical norm ISO15189 and the requirement
      for CE IVD marking. This will allow commercial developments (kits, protocols...) realized
      with the industrial partner Spot-to-lab
    

Detailed description: 
      Analyses of blood spotted and dried on a matrix (DBS), has been used since the 1960s in
      clinical chemistry neonatal screening. Since then, many clinical analytes, including nucleic
      acids, small molecules and lipids, have been successfully measured using DBS.

      DBS collection is in fact less invasive than classical venous puncture, it can be carried out
      by the patient at home and shipped by regular mail with no particular risk of contamination.
      The use of DBS in routine for the detection of transmissible diseases, as well as for the
      follow-up of chronic disease like diabetes, represent a safer and less costly evolution of
      clinical biology for the society.

      However the routine use of DBS is yet is limited. The major limitations of using DBS are
      represented by the small blood volumes associated with DBS sampling (5-10 μL) and by the
      limited possibility to detect peptides and proteins.

      In this program, we will address this issue by adapting to DBS mass spectrometry (MS)
      quantification of proteins/peptides. This relies on the detection of distinctive proteotypic
      peptides (peptides which sequence is specific to a unique protein). The specificity of such
      assays using triple quadrupole mass spectrometer is based on the capability to detect
      peptides by three molecular characteristics: retention time, precursor ion mass (m/z) and
      fragment ion mass (m/z). The combination of the precursor ion mass and the fragment ion mass
      z, highly specific, is called a transition. This approach is named when several peptides are
      detected in a single run "multiple reaction monitoring" or MRM. Using this approach, the
      direct analysis of the trypsin digest of blood samples is possible without additional sample
      fractionation.

      In a series of preliminary experiments, we could detect on single DBS puch of 6mm of
      diameter, 35 plasma proteins. Several proteins are of clinical relevance such as
      apolipoprotein A, B, C, ceruloplasmin, haptoglobin, plasminogen, transthyretin (prealbumin)
      or serum albumin. We will extend the range of blood protein detected by MS. Focus will be put
      on select biomarkers to generate clinically relevant panels that can be used for patients
      monitoring, nutrition monitoring and for the follow-up of frailty in elderly people .

      Innovative workflows to obtain more rapid, efficient and costless detection will be
      developed. We will also evaluate a new type of DBS card (Noviplex™) which collects plasma
      instead of whole blood, and is expected to achieve better clinical concordance of the results
      between DBS and classical sampling. The detection of the relevant clinical analytes will be
      validated on available patient samples in accordance with the clinical norm ISO15189 and the
      requirement for CE IVD marking. This will allow commercial developments (kits, protocols...)
      realized with the industrial partner Spot-to-lab. This start-up has already put on the market
      DBS analyses resulting from previous collaborative research. Being able to measure
      peptide/proteins from DBS in parallel with other clinical analytes also developed by
      Spot-To-Lab (vitamin D, HbA1c…) represents a breakthrough which will gives major perspective
      to the use of DBS in clinical chemistry for disease detection and monitoring.
    

Intervention name(s): clinical biology analyzes spectrometry mass
Intervention type(s): Biological
Intervention description(s): clinical biology analyzes spectrometry mass
Observational model: Case-Control
Time perspective: Cross-Sectional
Sampling method: Probability Sample
Study population: 
        Samples will be selected in a biobank from patients in neurology and geriatry units who
        gave their informed consent. Samples will be represented by leftover from blood sampling
        realized for the care and the determination of the concentration of blood analytes,
        including, albumin and CRP.
      
Biospecimen description: 
      Dried whole blood spots on filter paper and plasma