This study aims to evaluate a prototype device detecting zinc protoporphyrin-IX fluorescence non-invasively from the intact oral mucosa in children. The prototype device has shown high sensitivity and specificity in women after delivery for iron deficiency. Children are at increased risk for iron deficiency and prevention methods are not established jet. Zinc protoporphyrin-IX is an early indicator of iron deficiency and may be more sensitive than other established parameters. The prototype device is used to measure the erythrocyte zinc protoporphyrin-IX/heme ratio in children aged 9 months to 5 years. Children in this age are at increased risk for iron deficiency as they are growing rapidly and iron deficiency in this age may affect the neurodevelopment and immune system adversely. It is proposed that these effects cannot be rectified by iron supplementation in later years. The results from the non-invasive measurements are compared to reference measurements of the erythrocyte zinc protoporphyrin-IX/heme ratio from residual blood samples from the same patients and to other indicators of iron status, including hemoglobin, ferritin, serum iron, transferrin, transferrin saturation and soluble transferrin receptor.

This trial is a proof-of-concept study using a prototype fiber optic fluorometer to acquire autofluorescence spectra in children aged 9 months to 5 years and determine the erythrocyte zinc protoporphyrin-IX fluorescence intensity from these spectra. The non-invasively determined fluorescence spectra are evaluated to provide a quantitative measure of the erythrocyte zinc protoporphyrin-IX/heme concentration ratio. These values are primarily compared to an erythrocyte zinc protoporphyrin-IX determined by HPLC from residual blood samples from the same subjects and secondarily to erythrocyte zinc protoporphyrin-IX/heme ratios determined using a commercial hematofluorometer (AVIV, model 206d) and other indicators of iron status, including hemoglobin, ferritin, serum iron, transferrin, transferrin saturation and soluble transferrin receptor

This study could help to establish the non-invasive fluorescence measurement of zinc protoporphyrin-IX as a rapid, easy to use means for point-of-care screening for iron deficiency in resource-limited settings lacking laboratory infrastructure.

Inclusion Criteria:

• Children aged 9 months to 5 years
• Planed blood sampling, independently from this study
• Informed written consent to participation´s guardian in the study

Exclusion Criteria:

• the ability of the guardian is not given to approve the consent
• transfusion of blood products before entering the study
• blood sampling is not planed for clinical investigations

Children aged 9 months to 5 years

The principal investigator (PI, Prof. Dr. Dr. B. Koletzko) has access to the study data. The data may be shared with other researchers for specific research purposes if a written request with detailed description of objectives and goals, workplan and statistical analysis plan, strategy to protect data from other uses, publication strategy, and description of the research team and its qualification is provided. Based on the evaluation of proposals, the PI and study team will decided on a case by case basis which data can be provided.