The diagnosis of iron deficiency in hospital patients can be difficult in the presence of inflammation. A raised serum transferrin receptor (sTfR) level is useful as a marker of iron deficiency as it is unaffected by inflammation. However, diseases that cause an increase in erythropoietic activity can also result in a raised sTfR level. In South-East Asia, the prevalence of thalassaemia trait is high. As thalassaemia trait is associated with ineffective erythropoiesis and therefore an increase in the sTfR level, we studied the influence of thalassaemia trait on the diagnosis of iron deficiency in hospital patients. Among 431 patients with different combinations of iron deficiency, alpha- and beta-thalassaemia trait, we found that the sTfR level is an excellent diagnostic test for iron deficiency only in patients without thalassaemia trait. alpha-Thalassaemia trait worsened its diagnostic accuracy and beta-thalassaemia trait rendered it a non-diagnostic test. We conclude that in populations with a high prevalence of thalassaemia trait, the sTfR level is not useful in diagnosing iron deficiency unless the patient's thalassaemia status is known.

Daratumumab, a human immunoglobulin G1 kappa monoclonal antibody that targets CD38, is currently approved as monotherapy and in varying combinations with approved anti-myeloma regimens in both newly diagnosed multiple myeloma and relapsed refractory multiple myeloma. Originally developed for intravenous administration, the subcutaneous formulation of daratumumab (daratumumab and hyaluronidase-fihj) was recently approved by the US Federal Drug Administration and European Commission in 2020. In clinical trials, compared with the intravenous formulation, subcutaneous daratumumab (Dara-SC) has significantly shorter administration time (median first dose 7 h versus 3–5 min, respectively), lower rates of infusion-related reactions (median first dose 50% versus less than 10%, respectively), and lower volume of infusion (median 500–1000 ml versus 15 ml, respectively). Otherwise, the pharmacokinetics, safety profile, and efficacy are comparable. This review summarizes the pivotal trials that led to the approval of Dara-SC, highlights important clinical considerations for the use of Dara-SC, and provides practical guidelines for the administration of Dara-SC in the clinic.