That's a DNA test, it will only be negative if you are not the parent.
By not being a parent.
Equal
my qustion is can paternity test be wrong
You can not tell paternity by blood type. You can rule out paternity by blood type. For example, if both parents are O negative and the baby is type A positive, you can rule out paternity. The only way to determine paternity is by a DNA test. A few of the baby's hairs and the father's hairs can be sent to a lab. The lab can determine paternity.
A paternity test can determine if there is a parent-child relationship between two people. A paternity test would give genetic proof of that relationship.
see link below "Can you have a paternity test while you are pregnant?"
Test can do online
There are several options for a paternity test. You can try www.gtldna.net for a home test.
There is no 'score' on a paternity test. the man is either NOT the father or he could be.
see link below "Can you have a paternity test while you are pregnant?"
see link below "Can you have a paternity test while you are pregnant?"
No as it's unrelated to the cells carrying the DNA code, which are the White Blood cells.