Mportant impact on the children’s physical and cognitive development [8]. The controversy around the risk-benefit ratio of giving iron supplements to individuals exposed to malaria is still unresolved [9,10]. While a recent Cochrane review on this issue concluded that “iron supplementation does not adversely affect children living in malaria-endemic areas and should not be withheld from them” [11], the MedChemExpress I-BRD9 current WHO guidelines on iron supplementation to children exposed to malaria and high prevalence of infections recommend “against universal iron supplementation for children under 25033180 the age of two years living in malaria-endemic areas” [12,13]. Moreover, screening to identify iron-deficient children isIron Deficiency Diagnosis and InfectionsTable 1. Demographic and clinical characteristics of the study participants.Table 2. Proportion of children classified as iron deficient using internationally accepted cut-off values of iron markers.Characteristics Age (months)* Gender Male Female Fever Wasted (WAZ,22) Stunted (HAZ,22) (n = 179) Haemoglobin* Degree of anaemia Moderate Severe Very severe Inflammation (n = 176) P. falciparum (n = 170) Clinical Malaria (n = 170) HIV (n = 164) Parvovirus B19 Epstein-Barr virus Bacteraemia (n = 173) a-Thalassaemia (n = 41) Bone marrow iron content Absent Diminished Normal IncreasedResult 22.06 (13.67) 102 (57 ) 78 (43 ) 163 (91 ) 88 (49 ) 56 (31 ) 7.73 (1.97) 119 (66 ) 45 (25 ) 16 (9 ) 155 (88 ) 74 (44 ) 73 (43 ) 40 (24 ) 15 (8 ) 56 (31 ) 13 (8 ) 32 (78 ) 54 (30 ) 90 (50 ) 14 (8 ) 22 (12 ) Iron marker BI 78D3 chemical information ferritin (ng/ml) Ferritin (ng/ml) by CRP CRP,1 mg/dl CRP 1 mg/dl Ferritin 
(ng/ml) by age 3? months .5 months sTfR (mg/l) TfR-F index TfR-F index by CRP CRP,1 mg/dl CRP 1 mg/dl Plasma iron (mg/dl) Transferrin (g/l) Transferrin saturation ( ) TIBC (mg/l) MCHC (g/dl)* MCV (fl) by age ,2 years 2 years Obs. 173 173 21 152 173 6 167 163 163 163 17 146 176 176 176 176 173 174 110 64 70?1 73?9 #1.5 #0.8 22?50 2.0?.85 16?5 1? 32.0?6.8 50?00 7?40 0.83?.76 #1.5 12?00 30?00 Normal levels 30?Iron deficient n 21 15 12124 5776 35114 1 135 24 8165 1 77 14 47*Arithmetic Mean (SD). N = 180 and results expressed as n ( ) unless otherwise indicated. Abbreviations: HAZ, height for age Z score; Hb, haemoglobin; HIV, human immunodeficiency virus; WAZ, weight for age Z score. doi:10.1371/journal.pone.0050584.tAbbreviations: CRP, C reactive protein; MCHC, mean cell haemoglobin concentration; MCV, mean cell volume; Obs, observations; sTfR, soluble transferrin receptor; TfR-F index, transferrin-ferritin index; TIBC, total iron binding capacity. doi:10.1371/journal.pone.0050584.trecommended “with directed treatment of iron-deficient children only” [13]. This inconsistency between the evidence and what it is actually recommended is leading to different interpretations by policy makers and health personnel, and a lack of implementation of policies to prevent a significant global health problem. The diagnosis of IDA may be suggested by some signs and symptoms, but specially by blood tests indicating low haemoglobin, ferritin, and plasma iron levels. However, it has long been recognized that in developing countries interpretation of these and other biochemical tests is limited by the confounding effects of infection, inflammation and malnutrition [14,15,16,17]. Thus, precisely where IDA is most common, it is also more difficult to diagnose and therefore treat. A reliable, non-invasive tool for the assessment of ID in these population.Mportant impact on the children’s physical and cognitive development [8]. The controversy around the risk-benefit ratio of giving iron supplements to individuals exposed to malaria is still unresolved [9,10]. While a recent Cochrane review on this issue concluded that “iron supplementation does not adversely affect children living in malaria-endemic areas and should not be withheld from them” [11], the current WHO guidelines on iron supplementation to children exposed to malaria and high prevalence of infections recommend “against universal iron supplementation for children under 25033180 the age of two years living in malaria-endemic areas” [12,13]. Moreover, screening to identify iron-deficient children isIron Deficiency Diagnosis and InfectionsTable 1. Demographic and clinical characteristics of the study participants.Table 2. Proportion of children classified as iron deficient using internationally accepted cut-off values of iron markers.Characteristics Age (months)* Gender Male Female Fever Wasted (WAZ,22) Stunted (HAZ,22) (n = 179) Haemoglobin* Degree of anaemia Moderate Severe Very severe Inflammation (n = 176) P. falciparum (n = 170) Clinical Malaria (n = 170) HIV (n = 164) Parvovirus B19 Epstein-Barr virus Bacteraemia (n = 173) a-Thalassaemia (n = 41) Bone marrow iron content Absent Diminished Normal IncreasedResult 22.06 (13.67) 102 (57 ) 78 (43 ) 163 (91 ) 88 (49 ) 56 (31 ) 7.73 (1.97) 119 (66 ) 45 (25 ) 16 (9 ) 155 (88 ) 74 (44 ) 73 (43 ) 40 (24 ) 15 (8 ) 56 (31 ) 13 (8 ) 32 (78 ) 54 (30 ) 90 (50 ) 14 (8 ) 22 (12 ) Iron marker Ferritin (ng/ml) Ferritin (ng/ml) by CRP CRP,1 mg/dl CRP 1 mg/dl Ferritin (ng/ml) by age 3? months .5 months sTfR (mg/l) TfR-F index TfR-F index by CRP CRP,1 mg/dl CRP 1 mg/dl Plasma iron (mg/dl) Transferrin (g/l) Transferrin saturation ( ) TIBC (mg/l) MCHC (g/dl)* MCV (fl) by age ,2 years 2 years Obs. 173 173 21 152 173 6 167 163 163 163 17 146 176 176 176 176 173 174 110 64 70?1 73?9 #1.5 #0.8 22?50 2.0?.85 16?5 1? 32.0?6.8 50?00 7?40 0.83?.76 #1.5 12?00 30?00 Normal levels 30?Iron deficient n 21 15 12124 5776 35114 1 135 24 8165 1 77 14 47*Arithmetic Mean (SD). N 
= 180 and results expressed as n ( ) unless otherwise indicated. Abbreviations: HAZ, height for age Z score; Hb, haemoglobin; HIV, human immunodeficiency virus; WAZ, weight for age Z score. doi:10.1371/journal.pone.0050584.tAbbreviations: CRP, C reactive protein; MCHC, mean cell haemoglobin concentration; MCV, mean cell volume; Obs, observations; sTfR, soluble transferrin receptor; TfR-F index, transferrin-ferritin index; TIBC, total iron binding capacity. doi:10.1371/journal.pone.0050584.trecommended “with directed treatment of iron-deficient children only” [13]. This inconsistency between the evidence and what it is actually recommended is leading to different interpretations by policy makers and health personnel, and a lack of implementation of policies to prevent a significant global health problem. The diagnosis of IDA may be suggested by some signs and symptoms, but specially by blood tests indicating low haemoglobin, ferritin, and plasma iron levels. However, it has long been recognized that in developing countries interpretation of these and other biochemical tests is limited by the confounding effects of infection, inflammation and malnutrition [14,15,16,17]. Thus, precisely where IDA is most common, it is also more difficult to diagnose and therefore treat. A reliable, non-invasive tool for the assessment of ID in these population.