It sounds interesting, but the problem with this story is that I can't verify it. The doctor and her test results are nowhere to be found. Bummer.
However, even if this information about fabric frequencies has been—are you ready for it?--fabricated, I think that something like it must be true.
Think about the many verifiable scientific studies that have shown that toxicity levels in unkosher animals are much higher than toxicity levels in kosher animals. It's definitely bad for our health to eat animals that the Bible calls unclean. Elohiym was looking out for our health when gave us the kosher laws. If health concerns were (at least partially) behind the dietary regulations, then it's a good bet that health concerns are also behind the clothing regulations.
Some folks who have used linen and wool together report that the combination made them feel restless, lethargic, or ill. So at least there's anecdotal evidence of health problems associated with shatnez.
The Merits of Wool and Linen
Linen does have a lot of beneficial properties. It's durable, breathable, and dirt resistant. It filters certain types of cosmic radiation. It seems to aid in healing, and to prevent skin problems and bed sores. It's hypoallergenic. And fine linen gains softness and whiteness over time, as it gets repeatedly washed. Sounds like a wonder of nature if you ask me.
Wool has different but also beneficial properties. It's moisture-wicking, insulating, and breathable. It is also dirt-averse and flame-retardant. It doesn't hold on to body odors.
Since these are both great fabrics, why the prohibition against combining them? Beyond the possible health ramifications, the prohibition teaches us to maintain the natural order.
In the same verse that contains the prohibition against shatnez, we find two other instructions prohibiting certain mixtures:
"You are to keep My statutes. You shall not breed together two kinds of your cattle; you shall not sow your field with two kinds of seed..." (Lev. 19:19)
Linen comes from the flax plant, whereas wool comes from animals like sheep. These fabrics are products of entirely different kinds of organisms, one from the plant kingdom and the other from the animal kingdom. They simply don't belong together.
Note, however, that it was okay for the Israelites to wear a leather garment with a linen garment. I imagine that such a combination was allowed because the garments remained separate items; they were not blended together.
This does bring up an intriguing question: Can we use plant-based threads when sewing leather? Can we use woolen thread to sew leather that comes from a cow or a deer? Or should we perhaps be using sinews or hairs that come from the same animal as the leather? Admittedly, I don't have the foggiest clue about that. Since Scripture is silent on that topic, I would suggest not worrying about it. We don't want to fall into the error of the Jewish sages, who have added thousands of their own regulations to the Torah.
Don't MESS with That
Sadly, the genetic crimes committed by early man were largely to blame for YHVH's decision to wipe out all life on earth with a flood. According to the books of Enoch, Jasher, and Giants, there was a lot of miscegenation being practiced in the antediluvian world, which is why the Book Genesis states that all flesh had become corrupt. (The know-how came from rebel immortals called Watchers.) Those who follow Torah know better than to ever get close to such practices.
Back to the Earth
When I buy fabrics, I only get the ones that come from natural sources. I also prefer to avoid blends, so I aim for 100% wool, linen, or cotton. I may even have some pure silk ties or handkerchiefs. This is a new step of obedience for me, so my wardrobe is in a state of flux. It's a bit of a hassle replacing certain items, but it's worth it to me. There's no part of my life that shouldn't be directed by Elohiym.
Is it sin to wear blends of plant and animal fabrics if they aren't shatnez? It's hard to say. The Israelites didn't have access to some of the materials that we use for fabrics today, like bamboo, so there was no reason for Elohiym to mention them in the Torah. But if the spirit of the law is that we shouldn't mix diverse kinds, then I suspect that the newfangled blends are just as problematic as shatnez.
You'll have to decide for yourself whether or not to go the full nine yards, like I am. That's between you and the Father. But at the very least, stay away from shatnez if you value your well-being.