Figure 1.

Flow diagram of patients who submitted stool cards and had ferritin levels for a FERAD calculation. Less than 50% of patients turned in cards, and only 507 of those had ferritin concentration levels determined opportunistically and available from the computerized patient record system (CPRS). FERAD ratios in symptomatic (Sx) and asymptomatic (asym) patients totaled 36 and 461, where the results of a PCR COVID-19 test were unknown (unk). The proportion of stool cards delivered by postal mail was not substantially different from the known return proportion of 44% for occult blood card return, as determined for that time period at the Detroit VAMC.