Deficiency as a Rights Violation
When a person carries a measurable nutritional deficit (in magnesium, iron, potassium, folate, or any other essential substrate) and the standard of care neither tests for it nor corrects it once documented, the resulting harm is not a matter of clinical judgment alone. It falls within the scope of the right to health under Article 12 of the International Covenant on Economic, Social and Cultural Rights, read against the doctrine developed in General Comment 14.
The right to health under the Covenant is not absolute. It is a right of progressive realization, bounded by the maximum resources available to the State (ICESCR Article 2). But General Comment 14 identifies, at paragraph 43, a set of core obligations from which a State cannot exempt itself even under resource constraint. Among them: access to essential drugs as defined by the WHO Model List, the equitable distribution of health facilities and goods, and access to “minimum essential food which is nutritionally adequate and safe”. The correction of a documented physiological deficit, with a substrate that is inexpensive and available, sits inside this floor.
The failure to correct is not, in most cases, a refusal in the ordinary sense. It is architectural. The routine test does not name the deficit when it is present (see Calibrated for Nothing on the construction of the reference ranges, and The False Negative of Serum Potassium for the tissue-versus-serum problem in its clearest form). The deficit therefore never enters the differential, and the correction never enters the encounter. The clinician discharges the standard of care in good faith; the standard of care itself is calibrated to miss what a rights framing requires it to catch.
That architectural blindness is what turns individual clinical outcomes into a rights matter. Under civil-law doctrine, the obligation shifts from means (do your best with what the standard of care provides) toward results (the essential parameter shall be maintained). Medicine currently discharges the obligation of means. What the right to health requires, once the substrate is essential and the correction is trivial, is the obligation of results.
The doctrinal architecture has been in place since 2000. See The Instruments Already Exist for the reading of GC14 and the antiretroviral precedent, and A Litigation Brief for the standing, justiciability, and remedies analysis a jurist would need to develop the claim.