Would you need Assensing hits of 5+ in order to ID that the mage over there is actually an Infected (HMHVV I) individual, via the "accurate diagnosis of diseases or toxins which afflict the subject" category on the table in SR4A?

It seems that it should be lower, but that's the one that most closely fits the information sought.

cant find any quotes due to not being with books but that doesnt make sense due to them being dual natured and such. masking will change that problem abit but still should be eaiser then seeing if they have a normal infection.

Only some of the Infected are Dual-Natured actually, but yeah, with those it should make a difference.

It seems that a single success should be enough to notice something is odd... after all, that gives you "general health" and lets face it, the Infected are far from healthy. Hell, they're, in many ways, dead.

3 hits would be enough to pick up on the signs of HMHVV. 5 hits would be required to know which strain of HMHVV the subject is infected with.

Which would seem to say that in general, a vampire would have little to worry about, day-to-day (or night-to-night as it were) from being assensed and exposed as a vamp - three successes means a dicepool of 10ish, which is pretty high for a basic assensing isn't it? Yeah, specialists would blow 10 dice out of the water, but for your average security mage, that's a bit high.

It still feels like it should be easier, but who knows? Houserule it to the level you want, although it'd also be nice to know the exact RAW.

I would say (and that is what i do):

In the earlier stages you need more hits to see them as "infected"

When they "turned" as they have completed a metamorphosis i count them as a different "source" of aura. So i let a mage see a difference between Human, Ork, Elve, Vampire. (If he's got a knowledge skill about it, or has seen some before.

Otherwise he needs more hits so i can say: It's an infected elf etc.

Is it really possible to distinguish metahumans by their auras? I thought the metaraces are an expression of the astral shadow of the dna and unless you are looking through an optical microscope you may have a hard time staring at the molecules.

Well, i can elaborate on this:

Freshly infected (not turned): Is a mundane/magician/whatever which is diseased. To know he is diseased with something: 3 hits, to know what the disease is doing, 5 hits. (maybe add +1 for representing the sneakyness of HMHVV)
Infected himself: Now has critter powers, and a sure magic attribute. So now his magical "class" is "Infected" (as well as magician etc.), 2 hits to see that. He is at full health though, and on one hit will only count as "awakened"

And to seperating metahumans:
Yeah, just like i seperate fire-elementals from air-spirits... it should be easy to seperate trolls from elves. or even Ogres from orks. Or to detect Surge-Effects. I normaly tell the BIG differences at two hits (Troll or human) - as per different magical "class" and slight changes on 4 hits, cause of signature (yeah i know it is not really meant that way).

EDIT: You could also count a difference in genetic code as geneware though... and let them see it at 5 hits *g*.

Well, with 6 dice you have about 1:2 odds of having 3+ hits.

I'm no statistician, but that doesn't seem right somehow... you have a 33.33% chance of any single die coming up a hit (its one hit per three dice), so six dice would mean that you can, on average, expect two hits, right?

Math and I have never been very good friends though, so if anyone else can expand upon this, I would enjoy seeing it.

I'm no math wiz but I think the rough equation is:
x*(1/3)^y
Where x is the number of die you roll and y is the number of success you need.

So under that formula the odds are 0.222 or 2/9 of you getting 3 hits.

I don't think the formula is entirely correct because it doesn't count the odds of you getting 4 or more hits. I'm pretty sure you could map it out with some kind of calculus but I can't remember enough to guess the formula. Still, I'd be surprised if it broke 33%

Be lazy like me: Feshy´s diceroller with statistics function

Discounting glitches you are looking at a binominal distribution with a hit chance of 2/6.

And no, it does not break 1/3, it´s just 32%...