Single values of serum transferrin receptor and transferrin receptor ferritin index can be used to detect true and functional iron deficiency in rheumatoid arthritis patients with anemia

OBJECTIVE: To elucidate the use of serum transferrin receptor (sTfR) to distinguish between iron-deficiency anemia (IDA) and anemia of chronic disease (ACD), and to establish an improved scheme to identify functional iron deficiency (FID) in rheumatoid arthritis (RA) patients with anemia. METHODS: We studied 30 anemic RA patients whose iron status was confirmed by bone marrow examination and determination of the sTfR level, serum ferritin level, and sTfR-log ferritin index (TfR-F Index). All patients with diminished or exhausted iron stores (n = 18) received oral iron supplementation. RESULTS: Baseline values of sTfR and the TfR-F Index predicted the response correctly in all patients who received supplementation treatment and were normal in 10 of 11 patients with normal initial iron stores (ACD). CONCLUSION: The results of this study elucidate the roles of sTfR and the TfR-F Index in the differential diagnosis between IDA and ACD and provide direct evidence that these parameters are useful in detecting FID, irrespective of the concurrent iron storage status.     

Anemia in rheumatoid arthritis: high prevalence of iron-deficiency anemia in Indian patients

Anemia in rheumatoid arthritis (RA) is multi-factorial. We studied the prevalence and type of anemia and its correlation with disease variables in RA patients. Among patients with RA anemia was defined as hemoglobin ≤ 11 g/dl in females and ≤ 12 g/dl in males. Iron-deficiency anemia (IDA) was defined as serum ferritin ≤ 50 μg/dl. Disease activity was assessed by modified Disease Activity Score (DAS28). Of the 214 patients (183 females) anemia was found in 151 [70.6% (anemia of chronic disease—ACD in 51.6%, IDA in 48.4%)]. Except 13 all patients with anemia had active disease. mDAS-28 was higher (5.23) in anemic patients as compared to non-anemic patients (3.83; P < 0.005). Further, it was higher in patients with ACD (5.69) as compared to IDA (4.7; P < 0.001). In patients with ACD mDAS-28 had an inverse correlation with hemoglobin (r = −0.258, P < 0.05) and a positive correlation with serum ferritin (r = 0.359, P < 0.001). At 1 year 37.74% of patients with anemia had recovered. Anemia is a frequent extra-articular manifestation in RA. Significant IDA is present in nearly half the patients. Partial response to iron replacement suggests a component of ACD in these patients. Anemic patients with ACD had more active disease as compared with non-anemic patients or those with IDA.     

Serum transferrin receptor levels in patients undergoing evaluation of iron stores: correlation with other parameters and observed versus predicted results

Serum transferrin receptor (sTfR) concentrations were measured in specimens from 77 patients undergoing serum ferritin determination, and the results correlated with serum ferritin, serum iron, serum total iron-binding capacity (TIBC) saturation, erythrocyte mean corpuscular volume (MCV), and mean corpuscular haemoglobin (MCH). All parameters exhibited the expected inverse correlation with sTfR; this correlation was statistically significant for all parameters except serum iron concentration. The frequency with which iron deficiency (defined as absence of stainable marrow iron) is observed in patients with particular ferritin values in this centre was determined and used to estimate the expected number of iron deficient patients in the present study. In no setting were significantly fewer sTfR levels > 3.05 μg/ml observed than expected. However, significantly greater than expected numbers of elevated sTfR values were observed in patients with serum ferritin > 220 μg/l (P = 0.002). The results suggest that the sTfR level is probably not useful as a single test for identification of iron deficiency in unselected patients.     

High serum transferrin receptor level in anemia of chronic disorders indicates coexistent iron deficiency

Blood transferrin receptor (TR) level is largely determined by the quantum of erythropoiesis and by intracellular iron content of the cells of the erythroid lineage. Hence, a high serum TR level has been found to be useful in distinguishing iron deficiency anemia (IDA) from anemia of chronic disorders (ACD). In order to examine its potential role in the diagnosis of concomitant iron deficiency in ACD, we determined serum TR levels in 130 cases of ACD, in 25 cases of IDA, and in 40 normal adults. As expected, all patients of IDA had significantly higher serum TR levels compared to the normal subjects (4.2-19.2 microg/dL vs. 1.3-3.0 microg/dL) (P < 0.002). In 11/25 cases of IDA, the total iron-binding capacity (TIBC) was in the normal range although bone marrow iron store was absent and serum TR levels were high, thereby highlighting the superiority of TR level in the diagnosis of iron deficiency compared to TIBC. Although 54% (70/130) patients of ACD had normal or low serum TR levels (0.9-3.0 microg/dL) as expected, in 46% (60/130) of ACD patients, serum TR levels were high (3.2-11.0 microg/dL). Mean corpuscular volume, red cell distribution width, and transferrin saturation were significantly lower (P < 0.001) in the latter group of patients compared to the former, and these parameters resembled those in IDA patients. Also, serum iron was lower and TIBC was higher in this group of ACD patients compared to those with normal or low serum TR. All these features point to an "IDA-like" profile of ACD patients with high TR and support the possibility of co-existent iron deficiency in this subgroup of ACD patients. In light of these observations it would be prudent to treat ACD patients with high serum TR levels with iron replacement therapy.     

Is analysis of the reticulocyte haemoglobin equivalent a useful test for the diagnosis of iron deficiency anaemia in geriatric patients?

BackgroundIron deficiency anaemia (IDA) and anaemia of chronic disease (ACD) are common in elderly patients but there are no standard diagnostic criteria. The reticulocyte haemoglobin equivalent (Ret-He) is routinely measured by modern automated blood analysers and is an early indicator of iron deficiency. The aim of this study was to investigate whether the Ret-He level as calculated by the Sysmex XE-5000 automated blood analyser is a useful parameter for the diagnosis of IDA in a geriatric hospitalized population.MethodsIn a prospective study, blood samples were collected in 26 geriatric patients with IDA and 111 patients with ACD diagnosed according to generally accepted laboratory and clinical criteria. A blood count including Ret-He, mean corpuscular volume (MCV), mean corpuscular haemoglobin (MCH), mean corpuscular haemoglobin concentration (MCHC) and standard iron parameters was performed in each patient.ResultsHaemoglobin, Ret-He, MCV, MCH and MCHC levels were all significantly lower in IDA as compared to ACD patients. However, the area under the curve (AUC) was greater for MCH (0.87, 95% CI 0.78–0.95) and MCHC (0.86, 95% CI 0.76–0.96) then for Ret-He (0.828, 95% CI 0.73–0.93) and MCV (0.80, 95% CI 0.68–0.91). A Ret-He cut-off value of 26 pg had a sensitivity and specificity based on its optimal combination of 85% and 69% respectively.ConclusionAnalysis of Ret-He does not perform better than the classical red cell indices such as MCH and MCHC in differentiating IDA and ACD in geriatric patients.     

铁代谢指标测定对慢性病贫血并发缺铁的诊断意义

目的 :了解血清铁蛋白 (SF)、转铁蛋白饱和度 (TS)、血清转铁蛋白受体 (sTFR)及sTFR/log(SF)等外周血铁代谢指标对缺铁性贫血 (IDA)、慢性病贫血 (ACD)和慢性病贫血并发缺铁 (ACD/ID)的鉴别诊断意义。方法 :病例为IDA患者 18例 ,ACD患者 2 0例 ,其中 10例为ACD/ID患者。SF测定采用微粒酶免疫法 ,TS测定采用化学发光法 ,sTFR测定采用双夹心抗体酶联免疫吸附法。结果 :IDA患者的SF值、TS值显著低于ACD患者 ,其sTFR、sTFR/log(SF)值显著高于ACD患者。ACD患者中 ,ACD/ID患者与无缺铁的ACD(ACD/IR)患者间SF值无显著差别 ;但ACD/ID患者的TS值明显低于ACD/IR患者 ,而sTFR和sTFR/log(SF)值则显著高于ACD/IR患者。TS<4 0 %对ACD/ID检出的敏感性为 10 0 % ,特异性为 6 7% ;sTFR >30nmol/L对ACD/ID检出的敏感性为 90 % ,特异性为 82 % ;sTFR/log(SF) >2 0对ACD/ID检出的敏感性和特异性均为 90 %。结论 :新的铁代谢指标sTFR ,尤其是sTFR/log(SF)是传统铁代谢指标的必要补充 ,联合应用上述铁代谢指标可对ACD、IDA和ACD/ID患者进行准确的鉴别诊断。     

Factor V Leiden mutation carriership and venous thromboembolism in polycythemia vera and essential thrombocythemia

The aim of the present study is to evaluate in an elderly hospitalized population the diagnostic value of the serum transferrin receptor (sTfR) in distinguishing IDA (iron deficiency anemia) from ACD (anemia of chronic disease) as compared to conventional laboratory tests of iron metabolism, especially serum ferritin. In a prospective study, 34 patients with IDA and 38 patients with ACD (a chronic disorder in 23 and an acute infection in 15) were evaluated using iron status tests including serum transferrin receptor assay. The iron stores were assessed by bone marrow examination. sTfR levels were elevated (>28.1 nmol/L) in 68% of the IDA patients but also in 43% of the patients with ACD-chronic inflammation and 33% with ACD-acute infection. Serum ferritin was the best test to differentiate IDA from ACD patients. We conclude that serum ferritin is a more sensitive and specific parameter than the sTfR assay to predict the bone marrow iron status in an elderly anemic population.     

血清转铁蛋白受体对贫血患者鉴别诊断的临床意义

目的比较各项铁指标在慢性病贫血(ACD),缺铁性贫血(IDA)及ACD合并IDA中的变化规律,明确血清转铁蛋白受体(sTfR)的临床意义.方法设健康志愿者28例为对照组,同时设IDA组29例,ACD组 56例,分别进行血清铁(SI)、总铁结合力(TIBC)、运铁蛋白饱和度(TS)、血清铁蛋白(SF)及sTfR检测,并对26例慢性病患者做骨髓铁染色,根据sTfR值将ACD组分为(1)sTfR值正常组(ACD1组)27例(sTfR≤20.0 nmol/L ),(2)sTfR值升高组(ACD2组)29例(sTfR>20.0 nmol/L).结果 IDA组与其他各组相比,其中平均红细胞体积(68.0±11.3)fl为最小;SI、TS及SF值分别是(19.6±10.1) mg/L、(5.5±2.3)%和(4.3±2.8)μg/L,与对照组(81.7±30.6) mg/L、(27.0±12.0)%和(43.3±26.8) μg/L相比水平明显下降(P≤0.01);sTfR水平(67.2±40.3) nmol/L明显高于对照组(15.6±4.1) nmol/L,P≤0.01.ACD1组SF值(627.3±40.3) μg/L,明显高于其他各组(P≤0.01); SI(60.7±28.7) mg/L和TS(21.1±9.8)%与对照组差异无显著性(P>0.05),10例骨髓铁染色均无缺铁.ACD2组SF值(320.5±156.0) μg/L,高于对照组而低于ACD1组(P≤0.01),16例骨髓铁染色中14例显示铁缺乏,占88%.结论 sTfR值的升高有效地反映了体内铁缺乏状况,是诊断IDA更为敏感的指标,并且较少受慢性炎症性疾病的影响,可与ACD有效鉴别.     

Impaired erythropoietin responsiveness to the anaemia in rheumatoid arthritis. A possible inverse relationship with iron stores and effects of the oral iron chelator 1,2-dimethyl-3-hydroxypyrid-4-one

We investigated the serum erythropoietin (Epo) response in 11 rheumatoid arthritis (RA) patients without anaemia, 7 with RA and iron deficiency (ID) and 12 with RA and anaemia of chronic disease (ACD). In all patients the serum Epo was higher than in healthy subjects. Apparently this increase was insufficient to prevent anaemia in ID and ACD. Serum Epo correlated negatively with serum ferritin. Ten RA patients with ACD were treated with the oral iron chelator 1,2-dimethyl-3-hydroxypyrid-4-one (L1). No obvious toxicity signs occurred after one week of treatment. It effectively released iron from iron stores. The Hb rise (in 70% of the patients) was correlated positively with an Epo increase and negatively with a serum ferritin decrease. We conclude that a serum Epo increase does not overcome ACD. Epo response might correlate inversely with iron stores. L1 treatment effectively chelates iron from iron stores. The effects of L1 on erythropoiesis and serum Epo and its safety need further substantiation after prolonged treatment in more RA patients.     

Anaemia in rheumatoid arthritis: the role of iron, vitamin B12, and folic acid deficiency, and erythropoietin responsiveness.

Thirty six patients with rheumatoid arthritis (RA) (25 with anaemia) were studied to establish the role of iron, vitamin B12, and folic acid deficiency, erythropoietin responsiveness, and iron absorption in the diagnosis and pathogenesis of anaemia in RA. Iron deficiency, assessed by stainable bone marrow iron content, occurred in 13/25 (52%), vitamin B12 deficiency in 7/24 (29%), and folic acid deficiency in 5/24 (21%) of the anaemic patients. Only 8/25 (32%) had just one type of anaemia. The iron deficiency of anaemia of chronic disease (ACD) was distinguished by ferritin concentration, which was higher in that group. Mean cell volume (MCV) and mean cell haemoglobin (MCH) were lower in both anaemic groups, but most pronounced in iron deficient patients. Folic acid, and especially vitamin B12 deficiency, masked iron deficiency by increasing the MCV and MCH. Iron absorption tended to be highest in iron deficiency and lowest in ACD, suggesting that decreased iron absorption is not a cause of ACD in RA. No specific causes were found for vitamin B12 or folic acid deficiency. Haemoglobin concentration was negatively correlated with erythrocyte sedimentation rate in the group with ACD. Erythropoietin response was lower in ACD than in iron deficient patients. It was concluded that generally more than one type of anaemia is present simultaneously in anaemic patients with RA. The diagnosis of each type may be masked by another. Studies on pathogenesis of the anaemia are difficult as deficiencies generally coexist with ACD. Disease activity and, possibly, erythropoietin responsiveness are major factors in ACD pathogenesis.     

Erythroblast iron metabolism and serum soluble transferrin receptor values in the anemia of rheumatoid arthritis

OBJECTIVES: We have investigated in vitro erythroblast iron metabolism in the anemia of rheumatoid arthritis (RA). We also have examined the results in relation to bone marrow iron status in an attempt to explain the reported difference between serum soluble transferrin receptor (sTfR) values in anemia of chronic disease (ACD) and iron deficiency anemia (IDA) in patients with RA. METHODS: Bone marrow was examined in 29 anemic patients with RA, 9 healthy volunteers, and 6 patients with simple IDA. High purity erythroblast fractions were prepared from these bone marrow samples. Erythroblast surface TfR expression and iron uptake was assessed in vitro using (125)I-transferrin (Tf) and (59)Fe-Tf, respectively. The efficiency of erythroblast surface TfR function for Tf-iron uptake was determined by relating total iron uptake at 4 hours to surface TfR number. Serum sTfR values were measured for the RA anemia group, which was subdivided as RA-ACD (marrow iron present) or RA-IDA (marrow iron absent) on the basis of visible reticuloendothelial (RE) marrow iron stores. RESULTS: High purity (87 +/- 5%) erythroblast fractions were obtained from 35 of the 44 marrow samples. Erythroblasts obtained from patients with simple IDA showed a significant increase in surface TfR expression (P = 0.0003) and Tf-iron uptake (P = 0.001). RA anemia also led to a significant increase in erythroblast Tf-iron uptake (P = 0.016). This increase was not associated with an increase in surface TfR expression (P = 0.5), but was seen to occur as a result of a significant increase in the efficiency of surface TfR for Tf-iron uptake (P = 0.027). Within the RA anemia group, the increase in erythroblast Tf- iron uptake at 4 hours was more evident for RA-IDA (3.96 +/- 1.73 versus 1.66 +/- 0.66; P = 0.03) than for RA-ACD (2.69 +/- 1.18 versus 1.66 +/- 0.66; P = 0.057). This additional erythroblast response to absent RE iron stores led to a highly significant difference in serum sTfR values between RA-IDA and RA-ACD (40.2 +/- 14.0 versus 23.9 +/- 5.3 nmoles/liter; P = 0.001) CONCLUSIONS: An increase in erythroblast surface TfR efficiency for Tf-iron uptake compensates for the low plasma iron levels associated with anemia in RA and helps to maintain RA erythroblast iron uptake. With adequate RE iron stores, this increased efficiency limits intracellular iron deprivation and consequently reduces the need to increase surface TfR expression. As a result, serum sTfR levels in RA-ACD remain within the normal range. RA erythroblasts, however, are still able to respond to any additional worsening of the iron supply caused by absent RE iron stores. This additional response causes the highly significant increase in serum sTfR values seen between RA-IDA and RA-ACD.     

Erythroid abnormalities in rheumatoid arthritis: the role of erythropoietin.

Erythroid alterations were studied in 136 patients with rheumatoid arthritis (RA). Anemia was present in 75 cases. A definite diagnosis was determined in 65. The most frequent anemia was that of chronic disease (ACD) (43 cases); 14 patients with ACD presented with moderate to severe anemia. Prevalence of deficiencies were also high (15 cases had iron deficiency anemia, IDA). Serum erythropoietin levels were different in patients with RA compared with a healthy control group (p < 0.00001). Serum erythropoietin was increased in ACD (49 +/- 28.8 U/l) with respect to both RA (38.6 +/- 12.7 U/l, p = 0.0036) and controls (18.2 +/- 7.6 U/l, p < 0.00001). Although hemoglobin (Hb) was similar in ACD and IDA, serum erythropoietin in ACD was lower than in IDA (p = 0.01). There was a negative relationship between Hb and serum erythropoietin in ACD (r = -0.42, p = 0.005). In conclusion, almost 50% of patients with RA have anemia and ACD is the most frequent. As serum erythropoietin in ACD is blunted, patients with moderate to severe ACD are possible candidates for erythropoietin treatment.     

Serum soluble transferrin receptor in the diagnosis of iron deficiency in chronic liver disease

Fifty-one consecutive patients with chronic liver disease (CLD) underwent investigations of their iron status (full blood count, serum iron [Fe], total iron binding capacity [TIBC], transferrin saturation [TS], serum ferritin and serum soluble transferrin receptor [sTfR] level). Twenty-six patients were anaemic; 12 patients had iron deficiency, and 10 had iron deficiency anaemia (IDA). The median (range) sTfR in the IDA patients was 16.6 (11.2–24.8) mg/l, compared with 6.6 mg/l (11.2–24.8) in the 16 patients with anaemia due to other causes (P = 0.01). The sensitivity of sTfR for diagnosing iron deficiency in CLD was 91.6% (100% if only anaemic patients are included) and the specificity was 84.6%. Patients with haemolysis and recent blood loss may have falsely elevated sTfR levels. The results suggest that the sTfR is as useful as serum ferritin in identifying a potentially treatable cause of anaemia in CLD.     

Prediction and evaluation of the effect of iron treatment in anaemic RA patients

Summary In order to predict a haemoglobin (Hb) rise, in response to treatment with iron from simple erythrocyte and serological parameters, we treated 28 anaemic RA patients with oral iron during 6 weeks. Iron deficiency, present in 57% of patients, was assessed by staining a bone marrow aspirate for iron. Response rate in this group was 81% and median Hb increase was 0.8 mmol/l. After 6 weeks 69% of iron deficient patients were still anaemic. Patients without iron deficiency, considered as having anaemia of chronic disease (ACD), showed no significant Hb rise. The finding of a hypochromic microcytic anaemia was associated with a significant Hb rise. MCV showed highest specificity and predictive value (90 and 88%) and ferritin was the most valid predictor of a Hb rise within 6 weeks. Combination of low MCV and low ferritin resulted in a 100% specificity and predictive value indicating that patients with values below cut off point of these variables will definitely respond to treatment. Disease activity tended to decrease after 6 weeks, but this was not correlated with a Hb rise. It was concluded that a Hb rise can be predicted accurately by blood parameters. Using certain combinations, bone marrow aspiration is rarely necessary. Iron treatment is only useful in iron deficient RA patients, although active RA limits maximal Hb rise. In contrast to earlier findings, iron treatment had no deleterious effects on disease activity.     

ANAEMIA OF CHRONIC DISEASE: DIAGNOSTIC SIGNIFICANCE OF ERYTHROCYTE AND SEROLOGICAL PARAMETERS IN IRON DEFICIENT RHUEMATIOD ARTHRITIS PATEINTS

Erythrocyte and serological parameters were assessed in 44 anaemicrheumatoid arthritis (RA) patients to detect irondeficiencyas assessed by stainable bone marrow iron. The anaemia was normochromic normocytic in 60% and hypochromicnormocytic in 30% of those with anaemia of chronic disease (ACD). Iron deficiency was present in 55%and the anaemia was hypochromicmicrocytic in 54% and hypochromic normocytic or normochromicnormocytic in 21%. Iron absorption was found to be higher iniron deficient patients. In ACD patients, iron absorption correlatedinversely with ESR and CRP. For the detection of iron deficiency among RA patients withACD, the MCV showed the highest specificity (90%) and predictivevalue (87%). Serum ferritin was the most sensitive (82%) andvalid (86%) test. Combination of MCV, ferritin and transferrinresulted in 100% validity. It was concluded that iron deficiency can be detected accuratelywithout bone marrow aspiration using combinations of blood parameter. KEY WORDS: Iron deficiency, Diagnosis, Serum ferritin, Erythrocyte ferritin, Iron absorption, MCV, Transferrin     

Serum ferritin levels in anemia of rheumatoid arthritis

Thirty-five anemic patients with rheumatoid arthritis were studied to determine the relationship between serum ferritin levels and body iron status, as assessed by the grading of bone marrow iron stores. The incidence of greatly reduced or absent marrow iron stores was 60%. Peripheral blood smear, RBC indices, serum iron, and iron binding capacity correlated poorly with stainable marrow iron. Serum ferritin levels only correlated approximately with iron stores, and in iron deficient rheumatoid patients the levels were higher than would be expected in patients with uncomplicated iron deficiency. The study shows that reduced marrow iron stores is common in patients with rheumatoid arthritis, and that the serum ferritin concentration may provide a useful indication of reduced body iron stores in these subjects, but only if a range of normal values can be established for this disease.     

Causes of microcytic anaemia and evaluation of conventional laboratory parameters in the differentiation of erythrocytic microcytosis in blood donors candidates*

ABSTRACT

Context and Objective: Microcytic anaemia results from defective synthesis of haemoglobin in the erythroid precursors, causing a reduction in its mean corpuscular volume (MCV). The most common causes of microcytosis, without the increase in HbA₂ levels, are iron deficiency anaemia (IDA) and α-thalassemia. The aim of this study was to identify the causes of microcytic anaemia and evaluate the haematological parameters from blood donors deemed ineligible (due to the low haematocrit level) that would differentiate the IDA and α-thal, whether isolated or in association.

Methods: Genomic DNA was submitted to the polymerase chain reaction multiplex for the diagnosis of the most common allele deletions of α-thal and erythrogram and in order to verify haematological parameters. Iron deficiency (ID) was determined through the measurement of serum ferritin.

Results: Of the 204 samples, 82 (40.2%) were identified with ID, 24 (17.8%) with α-thal and 10 (4.9%) with ID associated with α-thal. In the α-thal with ID group haemoglobin (Hb), MCV, mean corpuscular Hb concentration (MCHC) and mean corpuscular Hb (MCH) values were significantly lower compared to the isolated α-thal. In the group with ID Hb, MCV, MCHC and MCH values were significantly lower compared to those with isolated α-thal. The α-thal with ID group, showed Hb, MCV, MCHC and MCH significantly reduced when compared to those with IDA.

Conclusions: This study showed that the values of haematological parameters, especially haematocrit, Hb, MCV, MCH, MCHC and red blood cell distribution width (RDW), are lower in patients with IDA, especially when associated with α-thal and therefore it may be useful to discriminate between the different types of microcytic anaemia.     

Iron deficiency anaemia in hospitalised patients: value of various laboratory parameters. Differentiation between IDA and ACD.

BACKGROUND: for the diagnostic evaluation of microcytic or normocytic anaemia in a heterogeneous group of patients, the value of newer parameters, such as zinc protoporphyrin (ZPP), plasma transferrin receptor (PtrfR) and PtrfR/ferritin ratio is not clear. We have performed a prospective study to determine the predictive value of these parameters and ferritin, for diagnosing iron deficiency anaemia (IDA). METHODS: sixty-two patients with Hb<8.2 (men) or <7.0 (women) and mean cell volume (MCV)<96 fl were included. Exclusion criteria were: known haematological disease, pregnancy, bone marrow suppression or iron therapy within the previous 7 days. Bone marrow examination was used as a golden standard to discriminate between IDA and non-IDA. RESULTS: twenty-four patients had depleted iron stores. We found that the reticulocyte response on iron supplementation correlated well with the iron-status of the bone marrow. Univariate analysis showed that ferritin, PtrfR/ferritin ratio, ZPP and PtrfR have significant predictive values for differentiating IDA from non-IDA. Interestingly, multivariate analysis revealed that ferritin was the only significant, independent predictor of IDA, with a cut-off point of 32 microg/l (sensitivity 79.2%, specificity 96.9%). CONCLUSIONS: the low sensitivity and specificity of ZPP, PtrfR and PtrfR/ferritin ratio render them insufficient to be used as a single 'best' test for the identification IDA in a non-selected group of anaemic patients and do not even add to the prediction if the value of ferritin is known.     

Serum soluble transferrin receptor in the diagnosis of iron deficiency in chronic liver disease.

Fifty-one consecutive patients with chronic liver disease (CLD) underwent investigations of their iron status (full blood count, serum iron [Fe], total iron binding capacity [TIBC], transferrin saturation [TS], serum ferritin and serum soluble transferrin receptor [sTfR] level). Twenty-six patients were anaemic; 12 patients had iron deficiency, and 10 had iron deficiency anaemia (IDA). The median (range) sTfR in the IDA patients was 16.6 (11.2-24.8) mg/l. compared with 6.6 mg/l (11.2-24.8) in the 16 patients with anaemia due to other causes (P = 0.01). The sensitivity of sTfR for diagnosing iron deficiency in CLD was 91.6% (100% if only anaemic patients are included) and the specificity was 84.6%. Patients with haemolysis and recent blood loss may have falsely elevated sTfR levels. The results suggest that the sTfR is as useful as serum ferritin in identifying a potentially treatable cause of anaemia in CLD.     

Microcytic anaemia in juvenile chronic arthritis

The degrees of anaemia and microcytosis in 100 patients with juvenile chronic arthritis (JCA) were analysed according to the pattern of disease and its activity. Microcytosis was common (40% of patients had a mean corpuscular volume (MCV) of less than 75 fl), sometimes severe (MCV less than 65 fl in 14 patients), and closely correlated with the severity of the anaemia. The degrees of microcytosis and anaemia were both directly related to disease activity as measured by the ESR, and were most severe in cases with the systemic form of JCA. In 50 patients iron status was assessed. The serum iron concentration was directly related to the MCV, whereas the serum ferritin was inversely related to MCV and haemoglobin concentration and directly related to the ESR. Bone marrow iron stores were normal or increased in 6 patients with severe microcytic anaemia. These data suggest that the anaemia of JCA is typically microcytic, and that this microcytosis is associated with the disturbance of iron metabolism seen in the 'anaemia of chronic disorders' rather than overall depletion of body iron.