RESUMO
BACKGROUND: The serum transferrin receptor (TfR) and the ratio of TfR to serum ferritin (TfR:SF) have been shown to be useful as early indicators of iron deficiency. OBJECTIVE: The objective of this study was to evaluate the performance of TfR and TfR:SF in the assessment of iron deficiency in infants and to analyze age-related changes in both variables. DESIGN: A total of 716 blood samples obtained from 515 healthy infants aged 8-15 mo were studied. RESULTS: In 144 samples in which all other laboratory indicators of iron status were within the reference range, the median and 95% CI for TfR and TfR:SF were 8.5 mg/L (95% CI: 5.9, 13.5) and 497 (95% CI: 134, 975), respectively. TfR and TfR:SF were significantly correlated with the other laboratory indicators of iron status. Furthermore, as the severity of iron deficiency progressed, there was a gradual increase in mean TfR concentration (P: < 0.00001; analysis of variance). The sensitivity of TfR > 13.5 mg/L and TfR:SF > 975 in the diagnosis of iron deficiency was 23.6% and 68.4%, respectively. The specificity was 98.3% and 63.3% for TfR and TfR:SF, respectively. The sensitivity and specificity of SF < 10 microg/L were 63.7% and 60.8%, respectively. Receiver operator characteristic analysis showed that TfR and TfR:SF were more accurate than was SF alone in the diagnosis of iron deficiency. CONCLUSIONS: TfR and TfR:SF showed age-related changes; TfR and TfR:SF appear to be better diagnostic tests for iron deficiency in infants than SF.
Assuntos
Ferritinas/sangue , Deficiências de Ferro , Receptores da Transferrina/sangue , Envelhecimento , Contagem de Eritrócitos , Índices de Eritrócitos , Feminino , Hemoglobinas/análise , Humanos , Lactente , Masculino , Curva ROC , Valores de Referência , Sensibilidade e EspecificidadeRESUMO
The present investigation was undertaken to assess the efficacy of oral iron supplementation during pregnancy by using a gastric delivery system (GDS). Three hundred seventy-six pregnant women between 16 and 35 y of age and 14 and 22 wk gestation were selected if mild anemia was present (hemoglobin concentration 80-110 g/L). The participants were randomly assigned to one of three study groups given no iron, two FeSO4 tablets (100 mg Fe) daily, or one GDS capsule (50 mg Fe) daily. Blood was obtained initially and after 6 and 12 wk for measurement of red blood cell and iron indexes, including serum transferrin receptor. There was a significant and comparable improvement in hematologic and iron-status measurements in the two groups of women given iron whereas iron deficiency evolved in women given no iron supplement. We conclude that by eliminating gastrointestinal side effects and reducing the administration frequency of an iron supplement to once daily, a GDS offers significant advantages for iron supplementation of pregnant women.
Assuntos
Ferro/administração & dosagem , Administração Oral , Adolescente , Adulto , Anemia/tratamento farmacológico , Cápsulas , Sistemas de Liberação de Medicamentos , Feminino , Testes Hematológicos , Humanos , Ferro/metabolismo , GravidezRESUMO
Serum transferrin receptor (TfR) levels were measured in 182 children with homozygous sickle cell (SS) disease, 47 with sickle cell-haemoglobin C (SC) disease and 41 normal (AA) controls on their eighth birthday. Highly significant elevations occurred in SS compared to SC disease and in SC disease compared to AA controls. Females had higher levels than males in controls but lower levels than males in SS and SC disease. In SS disease, serum TfR levels tended to rise with age from 2 to 8 years, the change within individuals correlating with a change in reticulocyte count (r = 0.38, P = 0.017) and fall in fetal haemoglobin levels (r = -0.51, P = 0.004). Serum TfR levels did not change with infection or painful crisis but were markedly elevated in hypersplenism and fell following splenectomy in these subjects. In the aplastic crisis, serum TfR levels tended to rise following clinical presentation and then fall, reflecting the reticulocyte counts. These observations are consistent with serum TfR levels being a useful indicator of the degree of erythropoietic expansion in sickle cell disease.
Assuntos
Anemia Falciforme/sangue , Receptores da Transferrina/análise , Transferrina/análise , Fatores Etários , Criança , Pré-Escolar , Feminino , Doença da Hemoglobina SC/sangue , Humanos , Lactente , Masculino , Fatores Sexuais , EsplenectomiaRESUMO
Transferrin receptors are used by rapidly dividing tissues such as bone marrow for the extraction of iron necessary for their metabolic requirements. As cells in the erythropoietic series mature, transferrin receptors are cleaved from the cell surface and may be measured free in the plasma. Serum transferrin receptors (STR) levels are therfore believed to reflect the extent of erythropoiesis and are elevated in anaemias associated with iron deficiency, haemolysis and thalassaemia and decreased in aplastic anaemia. Levels have been measured in stored sera from 182 children with homozygous sickle-cell (SS) disease and 42 controls with a normal haemoglobin (AA) genotype age 8 years (ñ 3 months) in a cohort study from birth. Levels is SS children (mean, SD: 38.3, 12.7) greatly exceeded those in AA controls (6.7, 1.9) (test = 32.1, p0.001) and were negatively correlated with total haemoglobin and foetal haemoglobin levels in both sexes but not with reticulocyte counts. The serum transferrin receptor level may be a useful indicator of the degree of eryreticulocyte counts. The serum transferrin receptor level may be a useful indicator of the degree of erythropoietic expansion in SS disease, and requires further study to determine its clinical value (AU)