She picked up the hypodermic needle and empty insulin bottle.
When you use an insulin bottle for the first time, write the date on the bottle.
Never leave insulin bottles in the sun or in your car.
The first time you use an insulin bottle, write the date on the bottle label.
Roll the cloudy insulin bottle until all the white powder has dissolved.
Label each insulin bottle the first time you use it.
Label each insulin bottle when it is used for the first time, and discard unused medicine after 30 days.
She checked the insulin bottles, but they were just as they'd always been, U 100.
More likely to have been the woman - only why on earth didn't she throw away the insulin bottle, or rinse it out?
It would explain why she didn't /throw away the insulin bottle.