After unprotected sex,when would be viable to undergo HIV Test or any STD test to crosscheck ?

After unprotected sex,when would be viable to undergo HIV Test or any STD related test to crosscheck whether we are infected or not ?

i don't think a doctor would ever recommend HIV testing, you had sex with a partner with unknown status, the chance of transmission is highly unlikely, sexually active people get tested once a year, people have no idea how rare this disease is, but if anxiety is what's bothering you, get tested just to put your mind at ease, but all i can tell you is that you're negative.

Immediately! If not, maybe within the week you had your intercourse. If really not, try when different health threats appear. But the third option is not possible with AIDS.

First tests for HIV should be done asap after risky sexual behavior, if negative a second in six months.

There are different incubation periods and window periods for every STI. The window period is the time from acquiring an infection before you will test positive (create antibodies that the tests look for)

For HIV:
75% of people will have seroconverted/test positive by 17-20 days
95% of people will test positive by 2 months
99% by 12-13 weeks
The other 1% could be people who have had HIV for many years and are in LATE stage HIV disease or people's whose immune systems are deficient for other reasons (chemo/radiation/organ recipients) Virtually everyone will test positive by 6 months

For other STI's, see your local clinic or your physician.

Every 6 months for the next 10 years. It can take up to 10 years for the HIV strand to show up in your blood. But, usually sooner. Most STDs will show in about 6 months. But my goodness, if you think you may have caught something, go get checked every month. And don't have sex with anyone even with condoms if you think you may be infected. Certain STDs are not stopped from spreading with a condom. There are plenty of womens clinics that will do it for free. Just do a search for it in your area.