Le khithi iyasebenza kunyango lwangaphambi kokuba isampuli ivavanywe, ukuze i-analyte kwisampuli ikhululwe ekubotshelelweni kwezinye izinto, ukuze kube lula ukusetyenziswa kwee-reagents zokuxilonga kwi-vitro okanye izixhobo zokuvavanya i-analyte.
Iarhente yokukhupha isampuli yohlobo lwe-I ifanelekile kwiisampuli zentsholongwane,kwayeIsixhobo sokukhupha isampuli yohlobo lwesibini sifanelekile kwiisampuli zebhaktiriya kunye nesifo sephepha.