Original article Table 4 Bone marrow iron status category results using the ntensive grading method Iron status category Functional iron deficiency (%) Normal iron (%) Iron stores deficiency (%) Functional and stores deficiency (%) 39.6 31.0 21.9 7.5 *OR = [odds in cases]/[odds in controls]. Cases Controls (n = 187) (n = 13) OR* (95% CI) p Value 46.2 7.7 38.5 7.7 0.7 (0.2 to 2.9) 0.9 5.4 (0.8 to 234.6) 0.1 0.5 (0.1 to 1.9) 0.2 1.0 (0.1 to 44.4) 0.9 children with deficiency of iron stores (1.9 (SD 0.7) mg/l) than in those with no deficiency (2.8 (SD 0.5) mg/l, p = 0.05), or with functional iron deficiency (2.6 (SD 0.6) mg/l, p,0.001). Children with deficiency of iron stores had a higher mean concentration of sTfR (21.7 (SD 12.5) mg/l) than those with normal iron stores (12.5 (SD 16.2) mg/l, p,0.001), or functional iron deficiency (11.4 (SD 6.0) mg/l, p,0.001). Children with functional iron deficiency had increased mean levels of CRP (126.7 (SD 85.6) mg/l) compared to those with iron stores deficiency (71.9 (SD 74.7) mg/l, p,0.001), or normal iron status (99.8 (SD 70.1) mg/l, p = 0.01). Ferritin, sTfR and CRP were determined for normal iron and iron deficiency states classified by Gale’s grading method (table 5). Mean log ferritin was higher in those with normal status cases compared to those who were iron deficient. The converse was true for mean sTfR levels. Mean CRP levels were increased in children with normal iron status compared to those classified as iron deficient (p,0.001). DISCUSSION The intensive histological grading method attempts to distin- guish four different iron states compared to the two categories using Gale’s method. The ability to distinguish states in which there is decreased cellular iron delivery to erythroblasts in the presence of adequate iron stores (termed functional iron deficiency), compared to states with limited availability due to lack of available iron in the reticular endothelial system, is of particular importance in areas of high malaria transmission and infection. Although some of the results of the biochemical tests are lacking and some of the aspirates were too poor to examine for iron, this study managed to assess a substantive number of bone marrow aspirates. There were no identifiable reasons for selection bias for the missing results. Functional iron deficiency, classified using the intensive histological grading method, was based on marrow findings alone. Although levels of CRP, a marker of an acute phase response,22 were mostly increased in all children, the finding of Figure 3 Error bar graphs for mean log ferritin, soluble transferrin receptor (sTfR) and C-reactive protein (CRP) concentrations for the different iron status classes using the intensive grading method. significantly raised levels among children with functional iron deficiency supports the hypothesis that these children have anaemia of inflammation. These children appeared also to have adequate iron stores as they had similar levels of ferritin and sTfR to children with normal iron status. The use of erythroblast iron to assess iron status has been used in other studies11 18 and has certain limitations. Marrow smears were counter-stained with Safranin, giving a uniform Table 5 Mean levels of Log ferritin, sTfR and CRP for iron status categories using Gale’s and Intensive grading methods Biochemical tests Log ferritin (mg/l)* sTfR (mg/ml){ CRP (mg/ml){ Gales’ grading method Normal Mean (SD) [n] 2.7 (0.5) [89] 95% CI 2.6 to 2.8 Mean (SD) [n] 11.8 (10.7) [156] 95% CI 10.1 to 13.5 Mean (SD) [n] 122.0 (6.7) [156] 95% CI 108.7 to 135.2 Iron deficiency 1.8 (0.7) [61] 1.6 to 2.0 22.7 (15.9) [86] 19.4 to 26.1 71.9 (8.5) [86] 55.2 to 88.7 Intensive grading method Normal 2.8 (0.5) [34] 2.6 to 2.96 12.5 (16.2) [56] 8.1 to 17.0 99.8 (70.1) [56] 81.5 to 118.2 Functional iron deficiency 2.6 (0.6) [44] 2.4 to 2.8 11.4 (6.0) [76] 10.0 to 12.7 126.7 (85.6) [77] 107.6 to 145.8 Iron stores deficiency 1.9 (0.7) [29] 1.7 to 1.2 21.7 (12.5) [44] 18.0 to 25.4 71.9 (74.7) [45] 50.0 to 93.7 Functional and iron stores deficiency 2.1 (0.8) 9 1.6 to 2.7 27.0 (28.3) 14 12.2 to 41.9 68.9 (64.9) 13 33.6 to 104.2 *Normal .30 mg/l. {Normal ,8.3 mg/ml. {Normal ,10 mg/ml. sTfR, soluble transferrin receptor; CRP, C-reactive protein. 688 J Clin Pathol 2009;62:685–689. doi:10.1136/jcp.2009.064451