Mae tua 85% o lwybrau cleifion yn galw am brofion diagnostig. Mae amrediad eang o brofion diagnostig i’w cael sy'n bwysig ar gyfer canfod clefydau a rhoi diagnosis, ac ar gyfer monitro triniaeth cleifion.
Around 85% of all patient pathways involve diagnostic testing.  A vast array of diagnostic tests exist that are important for the detection and diagnosis of disease, and for monitoring the treatment of patients.