oppostate, I know exactly what you're talking about.
Back in the 90's there was a JW doctor from Texas that was all about Applied Kinesiology. He really was a licensed chiropractor, but he went way beyond anything taught in legitimate chiropractic/medical school. For example, he claimed he had invented a "magic" box (about the size of a DVD case) that would detox and neutralize your allergic reactions to any food on a plate if you put it on the box for a few minutes. Of course, it could only work for so long and then you'd need to buy a fresh one. If you cut the box open (it was glued shut), the air would pollute the ingredients and it wouldn't work anymore. The sisters would almost swoon when Dr. Blanketyblank would come to town and "hold Court" at a local JW family's home so he could treat all the ailing sisters. Besides the box scam, he and his minions assistants would do the exact kind of testing you referred to. Last I heard, he got in some kind of trouble and doesn't come around anymore, but one of his former associates still does.
She does the same bogus testing you talked about, but also touts Iridology. That's where the practitioner looks into your eyes and tries to interpret what every little speck and color pattern means. They ask things like, "Did you break your arm when you were a child?" Or, "Did you ever have such-and-such an illness?" Of course, if you say you didn't, they quickly move on to the next wild ass guess question. If you said you did have whatever they asked about, they almost gleefully say, "See! I knew it! It's right there in your eye, plain as day!"
Now, I have no doubt that this particular woman is completely sincere, but she does become very defensive if anyone points out how ludicrous such a diagnostic technique is. All the while, adamantly denying that she is practicing medicine. She is only examining a patient friend, determining the cause of whatever their problem is, and prescribing suggesting whatever herb or natural remedy they should start taking. Fortunately, she just happens to have exactly what they need on hand, and can let them have it for a special price. You just know it's true because she once had a celebrity client and it did wonders for him.
I think the Witness mentality makes them especially susceptible to "alternative" medicine and outright quackery. Many are big into conspiracy theories. "The AMA, or the government, or fill-in-the-blank doesn't want you to know this because it would cost them too much money. They want you to stay sick so you'll keep paying out all that money to doctors and the drug companies." Etc., etc., ad nauseum...