Dr says hpt may take 4-5 weeks to show positive??

Melissa • Daughter 12/1/2016 ♥️ 32 weeker ToF PA MAPCAs ♥️ pregnant with #2 🌈 baby ♥️ MC 10/3/2018 👼

I am five days late for my second period after getting off of Depo Lupron but still this morning I had a negative hpt. I called my OBGYN to see if this was normal or if I should take something to kick start it etcetera. They said that a home pregnant test may not pick up the hormone until you are 4-5 weeks pregnant so I might either have to wait for a while or they might do blood work.

Is this true? I always thought that once you missed your period a hpt should be able to give you an accurate reading (positive or negative). Has this actually happened to anyone? It seems really incorrect...