5 to 6 days after conception might be too early to diagnose and false negative results might increase. After the 7th day post conception the chances of having a valid positive result increase.
Implantation of the embryo is usually done at a week after conception and even with an experienced ultrasound technician there still be a chance of having a false negative result.
These Q&A’s are for educational purposes and should not be relied upon as a substitute for medical advice you may receive from your physician. If you have a medical emergency, please call 911. These answers do not constitute or initiate a patient/doctor relationship.