Investigating hypozincemia and validity of plasma zinc measurements in infected patients

Hypozincemia is a well-known phenomenon in patients with infection caused by the activation of the acute phase response (APR). Zn status is still based upon plasma Zn levels in venous blood samples. Recent trials have questioned the validity of this measurement in infected patients. The aim of this study was to assess plasma levels of Zn, albumin and Zinc-binding capacity in patients during and following infection. Furthermore, to assess if an assay for albumin-corrected Zn could potentially replace or add knowledge to existing tools for assessment of Zinc-status. A prospective clinical observational trial was conducted. Associations between P-Zn, -Albumin, -Albumin-corrected Zn and Zn binding capacity were analyzed. Analyzes were based upon two venous blood samples drawn during and following infection, respectively. Twenty-three patients admitted to a medical ward showing paraclinical signs of infection were included in the study. Significantly lower levels of Zn and albumin were found during infection compared with the levels post-infection. These findings corresponded to the changes found in Zn binding capacity. About 52% of patients were deemed Zn deficient by plasma Zn levels during infection but after applying the correction for P-Albumin, all patients were found to be within normal ranges of Zn levels. Furthermore, we found no statistically significant difference between albumin-corrected Zn during infection and P-Zn post-infection. The new assay was found to accurately estimate the 'true' Zn levels in infected patients. Based on our findings, we propose albumin-corrected P-Zn as a promising new tool, which may result in more precise diagnostics and treatment.