Normally within 4 to 6 weeks, antibodies are formed, however for a test to said to be conclusive, 3 months time is enough where almost everyone with normal immune system, develops detectable amount of antibodies. Those with suppressed immune system due to meds, (chemotherapy for instance), this period is 6 months. 10 months time is extremely rare and not heard of
Extremely rare....In the sense is that possible???
"Extremely rare" among those with suppressed immune system ONLY, not for rest of the world. You are out of that count and for you, 3 months test is final and conclusive