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

Table 2

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 the whole sample ().

	Sensitivity %	Specificity %	PPV %	NPV %
RBCI	23.8	95.9	76.6	69.1
Ferritin	54.8	86.5	69.5	77.0
Ferritin/RBCI	66.7	86.5	73.7	88.2
Ferritin/TSAT/RBCI	66.7	91.9	82.4	83.1
Ferritin/TSAT/CRP/RBCI	66.7	93.2	84.3	83.4
Ferritin/TSAT/CRP/sTfR/RBCI	54.8	95.9	89.9	82.6
sTfR	80.9	93.2	86.7	89.6

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.