This can be read to be a +1 on any skill tests performed on Seeker cards which is solid since there are a lot of seeker events and assets that request skill checks. It doesn't help with any of the "For each point you succeed by" effects though.

Also, while an FAQ entry is yet to come out, I believe that assuming the difficulty of the test is 1 or 0 this will protect against even the autofail token. The autofail token sets your result to 0 and says you fail. Then this reaction kicks in and you succeed instead. Probably best use of that would be it means guaranteed success on Alchemical Distillation.

I have to say, to release Lab Coat in the same expansion as Research Notes, Gray's Anatomy, and Grim Memoir is a cruel joke. Clearly Lab Coat is better at serving cards from older expansions, but that's penalizing players getting into Arkham Horror LCG starting at Scarlet Keys.

Anyway, here are the 21 cards that Lab Coat makes a difference on (19 if you don't count the non-recommended options):

• "I've got a plan!" (and "I've got a plan!" (2))
• Alchemical Distillation
• Ancient Stone (only the lvl 0 version).
• Archaic Glyphs (Prophecy Foretold)
• Burning the Midnight Oil
• Cryptographic Cipher
• Deciphered Reality
• Divination (1) (and Divination (4)) (not recommended as you are penalized for succeeding by 0)
• Existential Riddle
• Expose Weakness (3) (not Expose Weakness (1))
• Fingerprint Kit (and Fingerprint Kit (4))
• Grim Memoir (not recommended since you want to succeed by 2)
• In the Know
• Map the Area
• Medical Texts (and to lesser extent, Medical Texts (2))
• Otherworldly Compass
• Persuasion
• Pocket Telescope
• Seeking Answers (and Seeking Answers (2))
• Strange Solution (and the Acidic Ichor and Freezing Variant variants)
• Unearth the Ancients (and Unearth the Ancients (2))

Now, the positive effect that Lab Coat has on most of these card amounts to a +1 boost, which given that it affects neither basic actions nor non- cards, is just inferior to a simple +1 boost. The truly unique to Lab Coat benefit is the ability to succeed tests on an draw. However, this requires your test to be difficulty 1 (or less), which at which point that extra protection is mostly for peace of mind; at best your Lab Coat protects you against a 1 in 14 chance.

In conclusion... I don't ever want to consign a card to binder fodder, but man is this card trying it's absolute best to be worthless. It's useless by itself (unless you count soak but once used as soak, it cannot be used for it intended purpose), and when in a combo, either the test is too trivial to warrant its use, or too high to make it anything other that a worse +1 . It should've cost 0. I like that now has a body slot asset, and a flavorful one too, but the card pool does not exist to make taking it worthwhile.

Limited applications, but say Darrell Simmons fails a skills test on a Seeker Asset by 2. Granny Orne intercedes and he’s down only one. He immediately triggers the reaction on his Lab Coat to pass by zero. Could be worth the setup if you’re already recurring Fingerprint Kit, on a higher difficulty, for example.