A harkar kiwon lafiya, gwaji wata hanya ce da ake bi don gano asalin kwayar cuta, ko kuma wani yanayi ne da alamomi ke bayyana yayin da gwaji ya tabbatar. Sau da yawa gane asalin kwayar cuta ta hanyar gwaje-gwajen likitoci. Abubuwan da ake bukata wajen gano asalin kwayar cuta, sun hadar da tarihi ko abinda ya bayyana na rashin lafiyar majinyacin, da kuma gwaje-gwajen likitoci a kan wanda ake kokarin bawa kulawa. Hanyoyin gwajin sune; daukar samfuri, wasu lokutan bincike kan gawar mamaci a kanyi la’akari da shi wajen gano asalin kwayar cutar da ta same shi. Sau da yawa ana fuskantar kalubale saboda mafi yawan alamun cututtuka na wahalar ganewa musamman yadda suke kamanceceniya da wasu. Misali sauyawar launin fata zuwa ja, yakan iya zama alamar cututtuka da dama, dan haka  kwararru basa iya gane takamaiman matsalar (gwajine kawai zai tabbatar). Yawanci idan za’a yi gwajin cututtuka hanyoyin da ake bi sun kunshi: Yayin hada bayanan mara lafiya, wanda suka hada da asalin jinya daga bakin yan uwan majinyacin ko kuma na kusa da shi, sannan sai gwaje-gwajen lafiya.