On Saturday, January 18, 2020 at 4:11:06 PM UTC-5, KC JONES wrote:
I've had a germicidal lamp more or less in storage for a number of
years, but recently brought it out to sterilize a room where a person
had been sick. However, I don't know if it still emits the germ killing
UVC spectrum. What's a quick way I could tell for sure? Thanks.

It's a good question (if not a good use.) Amazon is full of air purifiers that include UV light inside the enclosure. That light must degrade over time, if it even works at all.

A quick google says change the bulb every 12 months. I bet it isn't cheap, either.

So, A your lamp probably kills germs for about 6 inches, and B it's probably worn out by now anyway.