Background: Zinc is an essential trace mineral in the human body and is thought to be one of the most common micronutrients to be deficient. Zinc is needed for proper metabolism and immune system function. Zinc is a co factor in over 100 enzymatic reactions and is used for protein and DNA synthesis, cell division, wound healing and sensations of taste and smell. Normal serum zinc levels are between 0.66 mcg/mL to 1.10 mcg/mL. According to a study published in 2021, zinc is significant for boosting antiviral immunity and zinc deficient individuals are susceptible to severe viral infections and viral-bacterial coinfections. Limited data is available on the trends of Zinc testing in hospitalized patients. The purpose of this study is to evaluate the trends of serum zinc level testing at UMMC and the number of reported values outside normal limits
Methods: We performed a retrospective observational study of all inpatients aged 18 and over who received the Serum Zinc level at UMMC from January 1, 2013 to September, 2021. Patient Cohort Explorer was used to obtain de-identified patient data from EPIC. We obtained the data for hospitalized patients on whom the serum Zinc level was ordered. Microsoft Excel was used to do the calculations.
Results: Serum Zinc level was ordered 534 times on 480 patients during 433 hospital encounters from January 1st 2013 to September 30th, 2021. 23, 22, 20, 55, 64, 73, 163, 70, 44 tests were done annually from 2013 to 2021. 285 tests were done in females and 249 in males. About 239 tests were done in African Americans and 277 tests were done in Caucasians. Of the 534 tests, 293 tests (54.86%) came back with level < 0.66 mcg/ml, the lower cut off value. Only 15 tests (2.8%) came back over the upper limit of >1.10. Most of the tests (494) are done only once in the hospital while 40 tests were repeat tests during the same encounter. The median age of testing was 51.5. In patients less than 35 only 43 % were low while 54% were low after age 35 years. 285 tests were done in female and 156 came back low (54.73%). 249 tests were done in males and 146 (58.63%) were low. 137 tests were low in African Americans (57.32%) and 151 tests were low in Caucasians (54.51%)
Conclusions: To our knowledge this is the largest data sample with Serum Zinc levels in adult hospitalized patients. Interestingly about one in two samples that was tested for serum zinc level was lower than the minimum cut off. Even though zinc deficiency in hospitalization may not reflect zinc deficiency in general population, it is alarming to see the prevalence zinc deficiency in hospitalized patients. More studies are needed to see which patients are zinc deficient and if zinc deficiency is responsible for increased mortality and morbidity in hospitalized patients.