HCG injection after IUI - when should I test?

mebx • 37 TTC#1 low AMH, 5 MCs 😇 Pg with twins

I got my <a href="https://glowing.com/glow-fertility-program">IUI</a> on 20 August and then an HCG injection (5,000 ui) on 23 August.

When can I test to make I do not get a false positive?