Comparison of mean values and reference intervals for (A) RET-He and ferritin and (B) reticulocytes and haemoglobin, according to sex, body weight status and age
| Variables | RET-He (pg) | Ferritin (pmol/L) | |||||
| N | Mean±SD | P2.5 (95% CI) | P97.5 (95% CI) | Mean±SD | P2.5 (95% CI) | P97.5 (95% CI) | |
| (A) | |||||||
| Sex | |||||||
| Male | 497 | 30.01±1.52 | 26.44 (25.74 to 26.88) | 32.76 (32.52 to 33.06) | 135.38±98.36 | 31.00 (22.00 to 33.00) | 387.85 (308.36 to 440.70) |
| Female | 449 | 30.08±1.58 | 26.34 (25.58 to 26.68) | 33.18 (33.06 to 33.68) | 165.91±165.47 | 31.00 (22.00 to 33.00) | 598.00 (419.00 to 732.35) |
| P value | 0.486 | <0.001 | |||||
| Overweight | |||||||
| Yes | 123 | 29.87±1.55 | 26.31 (25.01 to 26.51) | 32.88 (32.55 to 33.65) | 155.18±111.66 | 31.25 (13.35 to 33.50) | 473.35 (366.70 to 600.90) |
| No | 801 | 30.07±1.55 | 26.50 (26.00 to 27.00) | 32.90 (32.60 to 33.20) | 147.97±136.35 | 31.00 (26.00 to 33.00) | 465.00 (417.01 to 529.75) |
| P value | 0.186 | 0.577 | |||||
| Age (months) | |||||||
| 2–6 | 167 | 29.55±1.53 | 26.02 (25.43 to 26.49) | 32.29 (31.67 to 32.72) | 250.35±251.78 | 31.90 (11.80 to 36.60) | 943.50 (798.40 to 1244.90) |
| 7–12 | 184 | 29.56±1.57 | 26.20 (25.40 to 26.79) | 32.49 (32.13 to 32.87) | 114.50±71.76 | 27.20 (23.40 to 33.30) | 311.15 (270.20 to 400.30) |
| 13–24 | 289 | 30.63±1.55 | 27.30 (26.88 to 28.10) | 33.30 (32.40 to 33.52) | 109.34±57.86 | 31.00 (26.00 to 39.00) | 248.80 (191.60 to 282.20) |
| 25–36 | 134 | 30.02±1.45 | 26.03 (24.60 to 26.57) | 32.47 (32.24 to 33.24) | 151.00±84.34 | 57.63 (43.25 to 66.25) | 346.50 (138.00 to 432.98) |
| 37–48 | 172 | 30.08±1.23 | 27.23 (26.75 to 27.80) | 31.97 (31.08 to 32.25) | 158.51±96.49 | 50.13 (35.25 to 58.68) | 349.88 (227.78 to 411.14) |
| P value | <0.001 | <0.001 | |||||
| (B) | |||||||
| Variables | Reticulocytes (×109 /L) | Haemoglobin (g/L) | |||||
| N | Mean±SD | P2.5 (95% CI) | P97.5 (95% CI) | Mean±SD | P2.5 (95% CI) | P97.5 (95% CI) | |
| Sex | |||||||
| Male | 497 | 59.14±16.58 | 33.12 (30.66 to 36.52) | 95.10 (86.40 to 100.20) | 123.9±7.4 | 111.0 (110.0 to 112.0) | 138.0 (135.0 to 139.4) |
| Female | 449 | 64.92±17.35 | 34.98 (30.24 to 36.16) | 102.38 (92.16 to 108.82) | 123.3±0.73 | 111.0 (110.0 to 112.0) | 137.0 (136.0 to 138.0) |
| P value | <0.001 | 0.196 | |||||
| Overweight | |||||||
| Yes | 123 | 62.61±15.99 | 35.22 (32.86 to 41.63) | 91.43 (82.56 to 98.30) | 125.0±7.9 | 111.1 (109.1 to 112.1) | 139.0 (135.9 to 141.0) |
| No | 801 | 61.61±17.26 | 34.80 (33.90 to 37.60) | 100.10 (94.40 to 105.70) | 123.4±7.2 | 111.0 (111.0 to 112.0) | 137.0 (136.0 to 138.0) |
| P value | 0.549 | 0.018 | |||||
| Age (months) | |||||||
| 2–6 | 167 | 58.50±15.19 | 34.82 (32.83 to 38.41) | 87.82 (75.02 to 92.63) | 119.7±6.5 | 110.0 (109.0 to 110.0) | 133.9 (130.9 to 135.9) |
| 7–12 | 184 | 62.03±16.83 | 39.22 (36.27 to 43.11) | 99.05 (71.90 to 112.80) | 121.9±7.0 | 111.0 (110.4 to 112.0) | 135.0 (133.0 to 136.0) |
| 13–24 | 289 | 61.96±15.75 | 35.74 (31.68 to 38.26) | 95.62 (91.68 to 100.46) | 124.0±6.8 | 112.0 (111.0 to 113.8) | 137.0 (134.2 to 138.0) |
| 25–36 | 134 | 64.17±19.85 | 27.46 (18.58 to 30.62) | 102.62 (75.04 to 113.22) | 126.2±7.3 | 113.3 (110.7 to 116.7) | 140.0 (134.1 to 143.1) |
| 37–48 | 172 | 63.11±19.05 | 32.25 (27.40 to 33.69) | 107.61 (97.76 to 122.94) | 126.7±7.0 | 115.0 (114.5 to 116.0) | 139.0 (129.8 to 141.0) |
| P value | 0.045 | <0.001 | |||||