Instruct: Classify Amazon reviews into positive or negative sentiment
Query: Painless on the wallet.

So I never knew my blood type and wanted to find out. My two options were (a) this card for $13, or (b) a lab test for $100.The card was the easier of the two options, as I suspected I have a 'common' blood type. If you suspect you have a rare or unusual blood type, you'll have to pony up the cash. The card will do basic ABO and Rhesus +-, but the Rhesus test isn't super sensitive.The most important part of doing the test yourself is: Read. The. Directions. Then read them again. The ones I got were probably translated from Dutch to German to English, making me scratch my head a few times. So make sure you _understand_ the instructions.Once you know what you're supposed to be doing, it's easy. The lancet is surprisingly effective. I was expecting a small puncture but it made a decent sized hole. Plenty of blood, provided you know what you're going to be doing with it.