Clinical utility of the soluble transferrin receptor and comparison with serum ferritin in several populations

Abstract

Soluble transferrin receptor (sTfR) and ferritin concentrations were measured in a variety of clinical settings to compare the ability of these two tests to identify iron deficiency. Among 62 anemic patients who either had a bone marrow aspirate performed or had a documented response to iron therapy, the diagnostic sensitivity and specificity of sTfR (at a diagnostic cutoff of >2.8 mg/L) were 92% and 84%, respectively, with a positive predictive value of 42% in this population. Ferritin (≤12 μg/L) had a sensitivity of 25% and a specificity of 98%. However, the sensitivity and specificity of ferritin could be improved to 92% and 98%, respectively, by using a diagnostic cutoff value of ≤30 μg/L, resulting in a positive predictive value of 92%. Ferritin and sTfR were also measured in 267 outpatient samples and 112 medical students. In the outpatient group, the two tests agreed in 73% of the samples; however, 25% of the samples had ferritin values >12 μg/L and increased sTfR. Among the medical students, there was 91% agreement between the two tests, but 7% of the samples had ferritin ≤12 μg/L and normal sTfR. Together, these data suggest that measurement of sTfR does not provide sufficient additional information to ferritin to warrant routine use. However, sTfR may be useful as an adjunct in the evaluation of anemic patients, whose ferritin values may be increased as the result of an acute-phase reaction.

Mass spectrometry evaluation of the hepcidin‐25 assay in the differential diagnosis of iron deficiency anaemia with concurrent inflammation and anaemia of inflammation in elderly patients

“…The optimal ferritin cut-off for ID in this study was 41.5 lg/L. Similar ferritin cut-off values for IDA have previously been reported by us and others (16)(17)(18). Human hepcidin was first determined in urine by mass spectrometry (7), and later in serum and urine by mass spectrometry (8) and ELISA (9).…”

Non‐anaemic iron deficiency – a disease looking for recognition of diagnosis: a systematic review

“…The threshold of <16 lg/L has a sensitivity of 75% and a specificity of 98% confirmed against bone marrow aspiration (32). The role of bone marrow aspiration to diagnose iron deficiency, however, remains unclear as its accuracy and relationship to serum iron status is uncertain (33,34). A ferritin threshold of 16 lg/L is the definition used by the WHO and has been confirmed in more recent studies in women (35); however, in young men, a ferritin threshold of <12 lg/ L may be more accurate (36).…”

Detection of iron restriction in anaemic and non‐anaemic patients: New diagnostic approaches

“…27 The decision thresholds for CHr, sTfR and sTfR-F index are in close agreement with data published earlier in causes of anaemia and indicate a good agreement with our multivariate classification system (diagnostic iron plot) published several years ago. 23 The iron plot is established as a diagnostic alternative to a binary outcome (iron deficient or not) applied to patients under investigation for iron state. 14,28 The For practical guidance, we propose a scoring system (Table 6), which is not as cost-intensive as the diagnostic plot.…”

“…However, the sensitivity is improved using a diagnostic cut-off value of ≤30 μg/L. 23 We therefore selected patients with a ferritin level of ≤30 μg/L as con- In patients with ferritin levels of ≥300 μg/L, no iron restriction was detected ( Table 3). The sTfR and the sTfR-F index (sTfR/log ferritin) were determined using the sTfR assays of Siemens (S) and Roche (R).…”