Optimització del temps de processat de l’iPRO, un processador de mostres d’immunofluorescència

Author

Soliva Dueso, Lluc

Abstract

Autoimmune diseases are, in developed countries, one of the most frequent. Detecting and diagnosing them early is key to improving the quality of life of patients. These diseases are divided into two groups: systemic and organ-specific. Among the different criteria established for the diagnosis of systemic diseases, one of the most relevant is the detection of antinuclear antibodies (Anti-Nuclear Antibody, ANA) in the blood serum of patients, and the technique par excellence or Golden Standard to detect them is the indirect immunofluorescence assay (Immuno Fluorescence Assay, IFA) in HEp-2 cells. The fluorescence patterns that occur during the binding of ANAs in HEp-2 cells can be related to different autoimmune diseases. This technique is also used to semi-quantify disease attachment through serial dilutions (titrations) at a 1: 2 ratio, usually ranging from 1/80 to 1/2650. Until now, IFAs and their titrations were performed using manual routines, but to streamline the workflow of autoimmunity laboratories, the process has begun to be automated. For this reason, BioSystems S.A. has developed an automated IFA sample processor: the iPRO. The objective of this work is to increase the processing capacity of the iPRO while maintaining the reading quality of the samples. Currently, using it to its maximum capacity for patients (65 samples with two titrations ─1 / 80 and 1 / 160─ in a total of eleven 12-pointer slides) the time of the routine validated by BioSytems S.A. in certain conditions it is 3h and 11min. To define the quality of the samples, a microscope with a fluorescence module has been used that, by means of imaging software, allows the normalized immunofluorescence (IFN (%)) of the samples to be calculated. time, while maintaining quality, is that of the design of experiments. To apply the method, eight variables have been selected that affect the total processing time and are easy to control, studying the behavior of the reference routine through hypothesis tests and statistical techniques. Specifically, the research unit has been defined, the behavior of the routes of each dilution has been analyzed, the difference between groups of dilutions 1/80 and 1/160 within a slide, and the behavior between slides. Also, in order to establish the IFN (%) value to be maintained, three genuine replications have been carried out, from which a target IFN (%) value has been extracted. Finally, the processing time has been reduced to 2h and 10min by modifying the conditions initially established in the protocol.

 

Director

Fernandez Ruano, Laura; Lecina Veciana, Martí; Carulla Sanmartí, Pere

Degree

IQS SE - Master’s Degree in Bioengineering

Date

2021-09-23