Last period 20.02, today 20.03 had spotting instead of my period, home pregnancy is negative. when to take hcg blood test?

Repeat test: It seems like it's only been one month since your last menstruation , which means that you still could have a period in the very near future. Try waiting one week and if you haven't had a cycle at that point then test yourself again.

Likely not pregnant: Home pregnancy tests are quite sensitive - if it is negative and you had spotting your period is about to start.