Evaluation of MITRA (TM) Volumetric Absorptive Microsampling (VAMS) as a Sampling Technique for β Isomerized Carboxy Terminal Telopeptide (β-CTX) and Type 1 Procollagen Amino Terminal Propeptide (P1NP) Determination Using Electro-Chemiluminescent Immunoassay (ECLIA).

Washbourne, Christopher (2022) Evaluation of MITRA (TM) Volumetric Absorptive Microsampling (VAMS) as a Sampling Technique for β Isomerized Carboxy Terminal Telopeptide (β-CTX) and Type 1 Procollagen Amino Terminal Propeptide (P1NP) Determination Using Electro-Chemiluminescent Immunoassay (ECLIA). Masters thesis, University of East Anglia.

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Abstract

Introduction
Type 1 collagen forms >90% of the organic matrix of bone. Bone is continually being remodelled, where type 1 collagen is broken down and renewed. During this, fragments created by the synthesis of new type 1 collagen or the breakdown of old type 1 collagen are released into the blood. The most widely used fragments for assessment of bone turnover are the synthesis product type 1 procollagen amino terminal propeptide (P1NP), and the degradation product β-isomerized carboxy-terminal telopeptide (β CTX). The concentrations of these molecules are conventionally assessed in serum or plasma obtained by venepuncture. Here I assess whether the concentrations of total P1NP and β-CTX can be ascertained from whole blood samples collected by volumetric absorptive microsampling (VAMS).

Methods
VAMS and K3-EDTA plasma samples were collected from military subjects (n = 44) enrolled in the UK Ministry of Defence’s ADAPT study at three timepoints. The microsamples and K3-EDTA plasma samples were analysed for P1NP and β-CTX by electrochemiluminescent immunoassay (ECLIA). The haematocrit (HCT) of the samples was assessed by automated cytometry on baseline whole blood K3-EDTA samples. P1NP and β-CTX concentrations for microsamples were back-calculated to plasma equivalent values (PEVs), based on the HCT obtained.

Results
PEVs for β-CTX showed positive linear correlation with a Pearson’s R of 0.900 when compared with conventional sampling. However, Bland-Altman analysis demonstrated the wide variability among this sample set. VAMS did not yield any valid results for P1NP due to assay interference from haemolysis and analyser sampling errors.

Conclusions
With improved processing of the microsamples, VAMS could be employed for β-CTX measurement. Further work is required to optimise the sample collection procedure to eliminate haemolysis of the sample and re-evaluate VAMS as a collection method for the analysis of β-CTX and P1NP.

Item Type:	Thesis (Masters)
Faculty \ School:	Faculty of Medicine and Health Sciences > Norwich Medical School
Depositing User:	Chris White
Date Deposited:	16 Mar 2023 09:18
Last Modified:	20 Mar 2023 12:24
URI:	https://ueaeprints.uea.ac.uk/id/eprint/91550
DOI:

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