Evaluating the role of long-term urine bio-banking on the stability of urine bio-markers in the diagnosis of pre-eclampsia

Date
2019-04
Journal Title
Journal ISSN
Volume Title
Publisher
Stellenbosch : Stellenbosch University
Abstract
ENGLISH ABSTRACT: The aim of the pre-eclampsia (PE) and eclampsia monitoring, prevention and treatment consortium is to develop a rapid diagnostic test for PE in pregnant women because early identification of PE would decrease the likelihood of maternal and perinatal mortality and improve antenatal care, management and treatment. The identification of potential bio-markers is thus of great importance in PE because urine is a non-invasive bio-specimen and has the potential to help predict PE since proteinuria can be detected and quantified in urine. The purpose of this exploratory study was to evaluate the long-term stability of selected analytes within preservative-free urine in a pre-eclampsia cohort. Calcium, Creatinine and total protein in long-term, stored urine samples were measured using both manual Siemens and Life Assay dipsticks and compared with high-throughput, laboratory measurements. Additionally, the diagnostic and prognostic potential of an Enzyme-linked immunosorbent assay (ELISA) -based, Adipsin or Complement Factor D (CFD) test for pre-eclampsia was evaluated. Furthermore, fresh urine samples were collected, and different processing and intermediate storage conditions were evaluated and compared to the medical research gold standard to determine to what extent pre-analytical variables could affect sample integrity. Albumin, Creatinine, Calcium, Urea and Total Protein were measured using high-throughput measurements. The results of the study showed that the measurements for the Siemen dipstick and Life Assay dipstick were significantly similar. However, no agreement was found between the dipsticks and high-throughput laboratory measurements. Adipsin was measurable using the ELISA assay despite the assay not being validated for frozen urine samples. Our results also showed that the measurements for Creatinine, Protein, and Calcium were impacted after sample storage at room temperature for 48 hours, highlighting pre-analytical variable has a great influence on sample integrity. This exploratory pilot study provided insight into the sample collection, handling, processing and long-term storage of urine bio-specimens and how each step of the process can have an impact. These insights led to an understanding of the limitations of this pilot study and can help to establish priorities for a larger study in terms of selected analytes to be measured, that could improve final research design and determine the best methods for data collection and analysis.
AFRIKAANSE OPSOMMING: Die Pre-eklampsia (PE) en eklampsia monitering, voorkomings- en behandelings konsortium beoog om 'n vinnige diagnostiese toets vir PE in swanger vroue te ontwikkel, aangesien vroeë identifikasie van PE die waarskynlikheid van moeder- en perinatale sterftes verminder en voorgeboortelike sorg, bestuur en behandeling verbeter. Die identifisering van potensiële biomarkers is dus van groot belang in PE aangesien urine 'n nie-indringende bio-monster het die potensiaal om PE te help voorspel, aangesien proteïurie in urine opgespoor kan word en gekwantifiseer kan word. Die huidige loodsstudie was om die langtermyn stabiliteit van selekteerde metabolite in nie-gepreserveerde uriene in n PE kohort te evalueer. Totale proteïen, kalsium en kreatinien in lang termyn gestoorde uriene was gemeet met die gebruik van die Siemens en Life Assay Dipstick en vergelyk met hoë-deurset laboratorium analise. Terselfdertyd, die diagnostiese en prognostiese potensiaal van n ELISA gebasseerde Adipsin/Komplement Faktor D (KFD) toets vir PE was ook geevalueer. Vars uriene was ook gekollekteer en op verskillende maniere geprosesseer en tydelik gestoor. Die verskillende kondisies was geevalueer en vergelyk met die goue standard om te bepaal tot watter punt voor –analitiese veranderinge monster intergiteit affekteer. Albumin, Kreatinien, Kalsium, Ureum en Totale Proteïen was gemeet deur hoë-deurset laboratorium metings. Die studieuitslae toon dat die metings vir die Siemen en die LifeAssay dipstiek aansienlik gelyk is maar geen ooreenkoms was tussen die dipstieks en die hoë-deurvoer resultate gevind nie. Dus word verdere navorsing en valideringstudies voorgestel. Adipsin kon gemeet word deur die ELISA-toets te gebruik, ondanks die feit dat die toets nie vir urienmonsters valideer is nie. Ons resultate wys ook dat monsters wat by kamertemperatuur vir 48 uur gestoor is, het n invloed op die metings vir Kreatinien, Proteïen en Kalsium en beklemtoon dat voor –analitiese veranderinge n groot invloed het op monster integriteit. Die verkennende studie het insig gegee in die versameling, hantering, verwerking en lang termyn storing van uriene monsters en hoe elke stap van die proses 'n impak kan hê. Hierdie insigte het ons begrip gegee van die beperkings van hierdie loodsstudie en sal help om prioriteite te vestig vir die groter studie in terme van die meting van selekteerde metaboliete, die verbetering van die finale navorsingsontwerp en die bepaling van die beste data-insameling en analise metodes.
Description
Thesis (MMed)--Stellenbosch University, 2019.
Keywords
UCTD, Bio-banks, Preeclampsia -- Diagnosis, Pregnant women -- Care
Citation