[tetramer]

The truth is, in medicine, we often fall into a trap of treating a number rather than the patient, and Vitamin D abnormalities are a classic example of this.

It's well known that by our current reference ranges, the vast majority of humans will be Vitamin D "deficient" but it's unclear what "sufficiency" truly is (https://www.nejm.org/doi/full/10.1056/nejmp1608005). Outside of known effects on bone health (e.g hyperparathyroidism), trials studying Vitamin D supplementation in a variety of disease states have not panned out.

All in all, I think this labeling is unlikely to cause significant harm given the unclear nature of Vitamin D deficiency, though I don't fully understand the need for this label in the first place as Vitamin D over-supplementation is unlikely as well.