Introduction: Zinc is an essential trace element for human
life and its deficiency affects human growth and development.
Serum zinc concentration (SZnC) provides useful information
in the clinical categorization of deficiency and
toxicity states.
Objectives: This paper presents a comparison study of
Flame Atomic Absorption Spectrometry (FASS) and the
Colorimetric method in the analysis of SZnC and hypozincemia.
Methods: The serum concentrations of zinc of 93 patients
(1 to 31 years old) with chronic diseases were used for analysis.
Statistical analytical: for SZnC, Pearson correlation coefficient,
simple linear regression analysis, Bland & Altman
method (B&A), and concordance correlation coefficient (CCC)
were valued; and for hypozincemia, the differences were
studied and Cohen’s Kappa index was used.
Results: The main results indicate the means of the SZnC
by both methods presented neither significant difference
(p=0.328) nor linear relation (R=0.18, p=0.077). Furthermore,
the percentage of cases of hypozincemia by the
Colorimetric method was almost double (13%) than by the
FASS (8%). There was only one coincident case in both methods
at <70 μg/dl.
Discussion: The Colorimetric method in hypozincemia
ranges predicted lower values with the FASS. This concordance
poor between both methods was corroborated with a
concordance correlation coefficient (CCC) lowly of 0.17.
Moreover, the Cohen’s Kappa index (-0.013) shown a concordance
poor between both methods, too. In other studies, the
variability of SZnC by Colorimetric method is more than FASS.
Conclusion: In summary, despite that, the mean of
serum concentrations of zinc by both methods is similar;
the diagnosis of cass with hypozincemia is not. The degree
of agreement between methods is poor, with a poor
strength of concordance to diagnosis hypozincemia.
Therefore, we recommended the use of FASS to evaluated
zinc status and diagnosis of hypozincemia, instead of the
Colorimetric method.
