Need advice: Partner visa 801/820 when to do the health examinations

Hi All,

My partner just submitted an application for Partner Visa 820/801 using online immi account from Australia. As soon the application was submitted, under "Actions required", we can see "Arrange health examinations". So when we go into this link, it generated a referral letter to undergo health checks for the visa. So my question is should we arrange the health checks immediately or should we wait until a case officer is assigned? Because the estimated processing time for this application would be 19 months to 24 months. If we do the tests now, it will be valid only for one year.

Has anyone come across this kind of situation before and appreciate if your experience could be shared.

Thanks in advance.