Unusual that the diagnostic card is not picking up your phone NFC reader, however each make and model of phone can vary the location of antenna.
A few things for you to try:-
What phone do you have? google NFC antenna location or check out THIS thread.
Make sure you take phone cover off.
do you have an access card or fob you can scan on your phone?
Try moving the diagnostic card very slowly. (my phone NFC pulses 5 x weak then one Strong)
Try it in a darkened room.
Can you try on another phone?
or an access reader or similar as they tend to put out more power.
do you have an NFC (13.56MHz) x Field detector? but the orientation of this is very important.
Also Highly unlikely that you can read an implant while still in the syringe. especially from a low power reader like a phone.
Anyway give those a try and let us know how it goes