Does CD21 blood test have to be on that day or can it be CD22??

[teacher1984]

Possibly a silly question but does anyone know? My CD21 this cycle falls on a Sunday so the doctors surgery isn't open. Is it ok to do the test on CD22??

The 'CD21' thing is a bit of a misnomer. The progesterone test should be done 7 days before your next period, which in a 28-day cycle would be CD21. But if you have a 32-day cycle for example it would be CD25.

Even if you do have a 28-day cycle, one day later will generally not make a huge difference so don't worry if you have to have it on the Monday.

Thank you very much for the info, very helpful x