Verification of coagulation analyzer Behring Coagulation System Xpand (BCS XP)

Uvođenje novog analitičkog analizatora u rutinski rad laboratorija obavezno zahtijeva provedbu verifikacije kako bi se ispitale analitičke značajke analizatora koje je utvrdio proizvođač. Cilj ovog istraživanja bio je ispitati može li se novi koagulacijski analizator Behring Coagulation System Xpand (BCS XP) koristiti za rutinski rad u Zavodu za medicinsku biokemiju i laboratorijsku medicinu KB Sv. Duh te može li poslužiti kao zamjena postojećem analizatoru istog tipa koji je u primjeni. Verifikacija analizatora obuhvatila je ispitivanje preciznosti, istinitosti, linearnosti metode i carryovera. Za ispitivanje preciznosti korišteni su komercijalni kontrolni uzorci u dvije koncentracijske razine koje predstavljaju normalnu i patološku plazmu. Za procjenu istinitosti korišteni su uzorci bolničkih pacijenata iz KB Sv. Duh i KBC Sestre Milosrdnice s ciljem pokrivanja čitavog mjernog koncentracijskog područja. Linearnost metode ispitana je iz svježeg humanog uzorka za raspon deklariranih vrijednosti od proizvođača za fibrinogen i D-dimer. Procjena carryovera odrađena je iz uzoraka normalne i patološke plazme u triplikatu. Uzorci s prisutnim interferencijama isključeni su iz daljnje analize. Rezultati analitičke verifikacije pokazali su da nepreciznost zadovoljava deklarirane kriterije od proizvođača za sve koagulacijske parametre. Ispitivanje istinitosti procjenom srednjeg odstupanja, obradom rezultata Passing-Bablok regresijom i Bland-Altman analizom pokazalo je postojanje razlike mjerenja novog analizatora za parametre PV (udio), PV (INR) i fibrinogen. Novi analizator u prosjeku mjeri više vrijednosti za PV (udio) i fibrinogen, a niže vrijednosti za PV (INR). Procjena mjernog područja, odnosno linearnosti provedena je za fibrinogen i D-dimer te prikazana jednadžbom pravca uz pripadne koeficijente korelacije te izračun biasa. Dobivene vrijednosti dokazuju postojanje linearne ovisnosti varijabli. Analizom uzoraka normalne i patološke plazme nije zabilježen značajan carryover. Stoga je moguće ustvrditi da je novi analizator Behring Coagulation System Xpand (BCS XP) spreman za uporabu u rutinskom radu. Razlike u mjerenjima određenih parametara u odnosu na postojeći koagulacijski analizator na Zavodu moguće su zbog uzimanja starog analizatora kao referentne metode koji je već dugo u uporabi. Zbog navedenog, rezultati mjerenja na novom analizatoru nisu u potpunosti usporedivi sa starim te bi trebalo izbjeći istovremenu uporabu obaju analizatora. U protivnom je o postojećim razlikama potrebno obavijestiti kliničare.The introduction of a new analytical analyzer into routine clinical biochemistry laboratories requires verification in order to test the analyzer's analytical features as defined by the manufacturer. The objective of this study was to explore whether the new coagulation analyzer Behring Coagulation System Xpand (BCS XP) can be employed for routine testing at the Department of Medical Laboratory Diagnostics at the Sveti Duh General Hospital. Additionally, the aim of the study was to investigate whether the new analyzer could replace the analyzer of the same type that is currently in use. The verification of the analyzer comprised tests of precision, trueness, linearity and carryover. The material used for precision determination included commercial control samples in two concentration levels: normal and pathological plasma. The material used for trueness evaluation consisted of patient samples taken from the Sveti Duh General Hospital and the Sestre Milosrdnice Clinical Hospital in order to cover the entire measurement concentration range. The material used for linearity testing included a fresh human sample for a range of fibrinogen and D-dimer values as declared by the manufacturer. The evaluation of carryover was based on normal and pathological triplicate plasma samples. Samples with detected interferences were excluded from further analysis. The results of analytical verification showed that imprecision meets the criteria declared by the manufacturer for all coagulation parameters. Trueness testing, which comprised several methods: bias evaluation, the Passing-Bablok regression analysis and the Bland-Altman analysis, revealed mean differences in the new analyzer for the following parameters: PT and PT INR, as well as fibrinogen. On average, the new analyzer records higher values for PT and fibrinogen, and lower values for PT INR. The evaluation of the measurement range, namely linearity, was conducted for both fibrinogen and D-dimer, and depicted by a linear equation along with its correlation coefficients and bias calculation. The obtained values demonstrate linear dependence between the variables. The carryover analysis showed that there is no significant carryover in measured samples. Therefore, it is possible to argue that the new analyzer Behring Coagulation System Xpand (BCS XP) is ready for use in routine work. The mean differences in certain parameters in relation to the existing coagulation analyzer used at the Department are possible because the old analyzer has been in use as the referent method for a long time. For the above reasons, the results obtained from the new analyzer are not completely comparable with the results obtained from the old analyzer, which is why the simultaneous use of the two analyzers should be avoided. Otherwise, clinicians should be informed about the existing differences