All perfect praise be to Allah, The Lord of the Worlds. I testify that there is none worthy of worship except Allah, and that Muhammad is His slave and Messenger.
Such an action is a form of forbidden deviation for the Prophetic Hadeeth related by Abu Dawood (with a good chain of narrators) that Ibn ‘Abbaas, may Allah be pleased with him, narrated that the Prophet said: “Whoever learns something of astrology has, in fact, acquired some knowledge of magic, and the more knowledge he receives (in stars) the more he learns of magic” [Abu Dawood]
In simple words, he is like the magician in misdeeds.
As for having a test before marriage to check the harmony of blood groups between the fiancé and fiancée for the sake of good and healthy offspring, then there is no harm in this as long as such an action is done under the control of reliable medical authorities.
For more benefit on graphology, palmistry and numerology, please refer to Fatwa 85039.
Allah knows best.