Določanje aktivnosti von Willebrandovega faktorja na osnovi testa ristocetinskega kofaktorja

Nenadić, Martina (author), Preložnik Zupan, Irena (mentor), Podgornik, Helena (co-mentor)

Von Willebrandova bolezen (VWB) je najpogostejša prirojena bolezen strjevanja krvi. V večini primerov se deduje avtosomno dominantno in v enakem obsegu prizadene oba spola. V redkih primerih najtežje oblike pa je dedovanje recesivno. Diagnostika te bolezni je kompleksna. Pogovoru z bolnikom in kliničnemu pregledu sledijo osnovne in specialne laboratorijske preiskave za opredelitev VWB. Aktivnost VWF lahko merimo z več metodami. V Specializiranem hematološkem laboratoriju Kliničnega oddelka za hematologijo, Univerzitetnega kliničnega centra v Ljubljani (SHL KOH UKCL), so aktivnost VWF do sedaj določali s sposobnostjo vezave trombocitov po standardni ristocetinski (RCo) metodi z agregometrom, ki pa je zamudna. V okviru magistrske naloge smo uvedli novejšo, avtomatizirano različico metode RCo, in sicer test VWF:GP1bR. Z njim smo analizirali obstoječe vzorce bolnikov (N = 50) in opravili primerjavo rezultatov z metodo za določitev aktivnosti VWF z ristocetinom (RCo). Klinično je metoda pomembna predvsem pri bolnikih z zmanjšano aktivnostjo VWF, kjer je diagnostika težja. Zato smo med 50 izbranimi vzorci tudi ločeno obravnavali tiste z zmanjšano aktivnostjo VWF. Na osnovi statistično analiziranih podatkov smo zaključili, da je novo uvedena metoda VWF:GP1bR sprejemljiva in primerna za prenos v vsakdanjo klinično prakso, saj izpolnjuje zastavljene analitične in klinične kriterije (nenatančnost v seriji in med serijami pri normalnih vrednostih aktivnosti VWF (KV < 5,5 %), pri nizkih vrednostih aktivnosti VWF (KV < 7 %)) in je v primerjavi z metodo RCo avtomatizirana. Z njeno uporabo pridemo hitreje do zanesljivih rezultatov, pri čemer je tudi natančnejša in cenejša od metode RCo. Rezultati obeh primerjanih metod so močno povezani oz. se ujemajo. Metoda VWF:GP1bR je povsem primerljiva tudi z metodo VWF:Ab oz. VWF:GP1b, ki jo za določanje aktivnosti VWF prav tako uporabljajo v SHL KOH UKCL.

• Language: Slovenian
• Keywords: aktivnost von Willebrandovega faktorja, von Willebrandova bolezen, metoda RCo, hemostaza, laboratorijska diagnoza
• Work type: Master's thesis/paper
• Organization: FFA - Faculty of Pharmacy
• Year: 2020
• PID: 20.500.12556/RUL-121249
• Publication date in RUL: 02.10.2020

Secondary language

• Language: English
• Title: Determining of von Willebrand factor activity based on a ristocetin cofactor assay

Abstract

Von Willebrand disease (VWD) is one of the most common congenital blood clotting diseases. It is mostly inherited in an autosomal manner, which means it affects both sexes equally. Rarely and in the more severe forms of the disease, it can be passed on in a recessive manner. The diagnosis of VWD is complex. Detailed medical anamnesis and patients' histories follow, along with basic and specific laboratory tests for determining VWD. Activity of VWF is possible to measure using different types of tests. The method which is currently used in the Specialized Hematology Laboratory of the Clinical Department of Hematology of the University Medical Center in Ljubljana (SHL KOH UKCL) is based on a standard ristocetin cofactor assay (RCo) measured by platelet aggregation and is particularly time consuming. The aim of this master's thesis was to introduce a new automated version of the ristocetin cofactor assay (VWF:GP1bR) into the laboratory. Existing samples of patients (N = 50) were analysed and we then compared the results found to those previously determined using the current RCo method. Clinically, the method is particularly important in patients with reduced VWF activity and the diagnosis is more difficult; therefore, we made a separate analysis for these samples. Based on a statistically processed data, we concluded that the new method VWF:GP1bR is acceptable for transfer to daily clinical practice, as the pre-defined clinical and analytical endpoints are met (within and between series imprecision for normal VWF activity (CV < 5,5 %) and for low VWF activity (CV < 7 %)). In contrast to the former RCo method by aggregometer, the new method VWF:GP1bR is automated; with it, a reliable result is achieved much faster and it is more accurate and less costly. At the same time, the methods strongly correlate and match. The new method VWF:GP1bR also corresponds to the results found using the method VWF:GP1b / VWF:Ab which is also used for measuring VWF activity in the laboratory: SHL KOH UKCL.

• Keywords: von Willebrand factor activity, von Willebrand disease, RCo method, hemostasis, laboratory diagnosis