Usefulness of Soluble Transferrin Receptor in the Diagnosis of Iron Deficiency Anemia in Rheumatoid Arthritis Patients in Clinical Practice

Table 4

Sensitivity, specificity, and predictive values of sTfR and standard parameters of iron status alone and in combination for the diagnosis of IDA or ACD/IDA () in patients with ().

	Sensitivity %	Specificity %	PPV %	NPV %
RBCI	28.6	91.9	67.1	69.6
Ferritin	38.1	94.6	81.0	73.1
Ferritin/RBCI	52.4	89.2	72.7	76.8
Ferritin/TSAT/RBCI	61.9	91.9	81.3	81.1
Ferritin/TSAT/CRP/RBCI	52.4	94.6	84.4	77.7
Ferritin/TSAT/CRP/sTfR/RBCI	52.4	94.6	72.7	76.7
sTfR	100	89.9	83.6	100

RBCI: red blood cell indices; IDA: iron deficiency anemia; ACD: anemia of chronic disease; ACD/IDA: anemia of chronic disease with concomitant true iron deficiency; TSAT: transferrin saturation; sTfR: soluble transferrin receptor.