Kratka analitička verifikacija metode za određivanje koncentracije PIVKA-II u ljudskom serumu

master's thesis

• Title (english): Brief analytical verification of the method for determination of PIVKA-II concentration in human serum
• Author: Dora Tisaj
• Mentor: Anita Somborac Bačura (mentor)
• Mentor: Lovorka Đerek (mentor)
• Committee member: Anita Somborac Bačura (predsjednik povjerenstva)
• Committee member: Lidija Bach-Rojecky (član povjerenstva)
• Committee member: Lovorka Đerek (član povjerenstva)
• Granter: University of Zagreb; Faculty of Pharmacy and Biochemistry; (Department of medical biochemistry and haematology); Zagreb
• Defense date and country: 2023-11-16, Croatia
• Scientific / art field, discipline and subdiscipline: BIOMEDICINE AND HEALTHCARE; Pharmacy; Medical Biochemistry

Abstract

PIVKA-II (engl. Protein Induced by Vitamin K Absence-II or Antagonist-II) abnormalni je oblik protrombina koji se sintetizira u stanju nedostatka vitamina K ili u prisutnosti njegovog antagonista koji inhibira aktivnost enzima gama-karboksilaze ovisne o vitaminu K. Povišene koncentracije PIVKA-II u neoplastičnim stanicama hepatocelularnog karcinoma (HCC) nastaju kao posljedica oštećenog procesa karboksilacije protrombinskog prekursora. U složenom procesu hepatokarcinogeneze PIVKA-II pospješuje staničnu proliferaciju, tumorski rast te pojavu metastaza. Nakon svoga otkrića ova je molekula postala predmetom istraživanja, a njene analitičke odlike poput zadovoljavajuće osjetljivosti i specifičnosti čine je optimalnim tumorskim biljegom u dijagnostici, nadzoru i liječenju HCC-a, bolesti koja bilježi visoku incidenciju i visoku stopu smrtnosti.
Cilj ovog diplomskog rada bio je procijeniti prihvatljivost analitičke metode za kvantitativno određivanje PIVKA-II u humanom serumu na analizatoru Snibe Maglumi 800 procesom verifikacije prije nego ona postane dio rutinskog rada u laboratoriju Kliničke bolnice Dubrava.
Za određivanje koncentracije PIVKA-II korištena je kemiluminiscentna imunometoda (CLIA), a verifikacija metode provedena je prema CLSI EP15-A2 smjernicama koristeći dva kontrolna uzorka čija se koncentracija mjerila u triplikatu tijekom 5 dana mjerenja. Proces verifikacije uključivao je procjenu preciznosti, točnosti, mjerne nesigurnosti te usporedbu s metodom implementiranom u Kliničkom bolničkom centru Rijeka.
Ostvareni rezultati za preciznost, točnost te srednju ukupnu pogrešku zadovoljili su postavljene kriterije prihvatljivosti. Rezultati usporedbe ispitivane metode s postojećom metodom prikazani Bland-Altmanovim prikazom te Passing-Bablockovom regresijskom analizom ne pokazuju postojanje ni konstantne niti proporcionalne pogreške koje bi bile statistički značajne. Međutim, uočen je nesklad u rezultatima kod nekih pacijenata zbog primjene različitih metoda određivanja istog analita što je dokaz neusporedivnosti imunokemijskih metoda. Kako bi se izbjegao rizik od klinički različitog tumačenja rezultata, potrebno je svakog pacijenta laboratorijski pratiti uvijek istom metodom.
Na temelju rezultata verifikacije, zaključuje se da novouvedena metoda kvantitativnog određivanja PIVKA-II u serumu zadovoljava postavljene kriterije prihvatljivosti te se kao takva može koristiti u rutinskom laboratorijskom radu.

Abstract (english)

PIVKA-II (Protein Induced by Vitamin K Absence-II or Antagonist-II) is an abnormal form of prothrombin that is synthesized in the state of vitamin K deficiency or in the presence of its antagonist that inhibits the activity of vitamin K-dependent carboxylase. Elevated concentrations of PIVKA-II in neoplastic cells of hepatocellular carcinoma (HCC) occur as a result of a damaged process of carboxylation of the prothrombin precursor. In the complex process of hepatocarcinogenesis PIVKA-II promotes cell proliferation, tumor growth and the occurrence of metastases. After its discovery, this molecule became the subject of research, and its analytical features, such as satisfactory sensitivity and specificity, make it an optimal tumor marker in the diagnosis, monitoring and treatment of HCC, a disease with a high incidence and high mortality rate.
The aim of this study was to assess the acceptability of the analytical method for the quantitative determination of PIVKA-II in human serum on the Snibe Maglumi 800 analyzer through the verification process before it becomes a part of the routine work in the laboratory of the Clinical Hospital Dubrava.
The chemiluminescence immunoassay (CLIA) was used for determination of PIVKA-II concentration, and verification of the method was performed according to CLSI EP15-A2 guidelines using two control samples whose concentration was measured in triplicate during 5 days of measurement. The verification process included an assessment of precision, accuracy, measurement uncertainty and a comparison with the method implemented in Clinical Hospital Center Rijeka.
The achieved results for precision, accuracy and mean total error met the set acceptance criteria. The results of the comparison of the tested method with the existing method shown by the Bland-Altman representation and the Passing-Bablock regression analysis do not show the existence of either constant or proportional error that would be statistically significant. However, a discrepancy was observed in the results of some patients due to the application of different methods of determination of the same analyte, which is proof of the incomparability of immunochemical methods. In order to avoid the risk of different clinical interpretation of the results, it is necessary to always monitor each patient using the same method in the laboratory.
Based on the verification results, it is concluded that the newly introduced method of quantitative determination of PIVKA-II in serum meets the set acceptance criteria and can be used in routine laboratory work.

• Keywords: PIVKA-II; imunokemijske metode; verifikacija; preciznost; točnost; mjerna nesigurnost; usporedba metoda
• Keywords (english): PIVKA-II; immunochemical methods; verification; precision; accuracy; measurement uncertainty; method comparison
• Language: croatian
• URN:NBN: urn:nbn:hr:163:245943
• Study programme: Title: Medical biochemistry; Study programme type: university; Study level: integrated undergraduate and graduate; Academic / professional title: magistar/magistra medicinske biokemije (magistar/magistra medicinske biokemije)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Open access
• Created on: 2024-01-25 14:06:38