soooo.....I think it's 48 hours and not 72 hours?

The 48 hours is in reference to the 'green pass/ EU digital covid certificate pass etc.
Prior to Aug. 31st (today) all you needed to get in to Italy was this "green pass/EU pass" or equivalent. In order to obtain this you needed either 1. vaccination that qualified, 2. negative test within 48 hours or 3. proof that you had covid and obtained certificate for that immunity. Given you are in the USA (I believe) that meant your CDC white card was sufficient as a comparative equivalent.

Now moving forward as of Today all travelers regardless of their vaccination status need to obtain a negative covid test 72 hours prior to arrival in Italy. You will still need that 'green pass/EU digital covid certificate' equivalent = your CDC card in order to access restaurants, trains, attractions etc. Hope that helps clear it up.

in any case if you are worried about it go get your test under the 48 hour timeframe and you meet the requirement of the 72 hours.

also worth noting that the above requirements are in addition to the European Digital Passenger Locator Form DPLF. This is a straight forward form for contact tracing purposes.

I understand that part but when I just completed my passenger locator form, it says I am agreeing to both the vaccine AND a test within 48 hours and not 72. So the fact it says both suggests to me the site has been updated. But maybe only partially updated. I will certainly keep watch with everyone else.

I plan to get my test within the 48 hour mark just in case and believe me, if this is the most stressful part of the new ordinance, that's okay with me. But I have a 20 hour flight time assuming everything is on time. My home airport does not do COVID testing. So that loss of 24 hours does make it a bit trickier for me as I assume it would for other people.

Kristen. I think the confusion is that both 48 and 72 are referenced on the directive from the Health Ministry . You can read it here. https://www.esteri.it/mae/en/ministero/normativaonline/decreto-iorestoacasa-domande-frequenti/focus-cittadini-italiani-in-rientro-dall-estero-e-cittadini-stranieri-in-italia.html
We are traveling to Italy via Heathrow and we too are confused as to which requirement fit those transiting through the UK. One would take the 48 hrs to mean UK residents. It is not clear. If you are a US citizen and are not flying via Heathrow it is 72 hours as noted on the directive.

Okay wow that's the clearest version of things I have read. Thank you!

So that is another weird thing I noticed. While the paper version of the passenger locator form asks about negative test and vaccination the digital website version that gives you a QR code does not ask about this. Also that form has not been updated since yesterday. I chose to complete the digital version instead.

Kristen: Here is a helpful site which may be used to calculates retroactively the number of hours from planned arrival to Italy to when a test should be taken to meet the required 48 or 72 hours since swab test. This site incorporate the time zone conversion since Italy is 7 hrs ahead from Chicago.

https://www.timeanddate.com/date/duration.html

And do we know if the self-administered, digitally proctored tests like Binax Now used for getting back into the States are accepted by Italy as well?

Yes
There have been reports here by some who have used
They are also recommended by the airlines as an accepted test

Thanks for the link Alex!