No, that's low risk and warrants no further testing. Here it's anything above 1:150 that's higher risk. My risk was 1:165 and I was initially very worried but the consultant and midwife were completely unconcerned, explained that hormone levels are variable and spent some time looking at other soft markers on the scan (none present at all). 20 week scan showed everything to be just as it should be too. It sounds high I know, but it really, really isn't.
That nuchal measurement is great. We had a measurement of 2.7mm which is considerably higher but as I said by 20 weeks, everything looked (and is) absolutely fine.
I do know how shocking the numbers can sound though. But if they had noted anything at all on the scan (and they do check a surprising number of things), they'd have told you. Remember it's a 161:162 chance of everything being fine which are surprisingly good odds. Your risks of all sorts of things that don't even enter your mind are much higher. It's just the one thing that they put a number on and actively talk to you about. Chances are that things are absolutely fine.