Ability of Ferritin, TfR, TfR/Ferritin Ratio and TfR-F Index to Identify Patients With Iron Deficiency
| . | IDA v ACD . | IDA + COMBI v ACD . | COMBI v ACD . | |||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| . | Ferritin . | TfR . | TfR × 100/Ferritin . | TfR-F Index . | Ferritin . | TfR . | TfR × 100/Ferritin . | TfR-F Index . | Ferritin . | TfR . | TfR × 100/Ferritin . | TfR-F Index . |
| False negative | 1 | 3 | 1 | 0 | 6 | 4 | 3 | 1 | 5 | 1 | 2 | 1 |
| False positive | 1 | 4 | 1 | 0 | 1 | 4 | 1 | 0 | 1 | 4 | 1 | 0 |
| True negative | 63 | 60 | 63 | 64 | 63 | 60 | 63 | 64 | 63 | 60 | 63 | 64 |
| True positive | 47 | 45 | 47 | 48 | 59 | 61 | 62 | 64 | 12 | 16 | 15 | 16 |
| Sensitivity | 0.98 | 0.94 | 0.98 | 1.00 | 0.91 | 0.94 | 0.95 | 0.98 | 0.71 | 0.94 | 0.88 | 0.94 |
| Specificity | 0.98 | 0.94 | 0.98 | 1.00 | 0.98 | 0.94 | 0.98 | 1.00 | 0.98 | 0.94 | 0.98 | 1.00 |
| Positive PV | 0.98 | 0.92 | 0.98 | 1.00 | 0.98 | 0.94 | 0.98 | 1.00 | 0.92 | 0.80 | 0.94 | 1.00 |
| Negative PV | 0.98 | 0.95 | 0.98 | 1.00 | 0.91 | 0.94 | 0.95 | 0.98 | 0.93 | 0.98 | 0.97 | 0.98 |
| Efficiency | 0.98 | 0.94 | 0.98 | 1.00 | 0.95 | 0.94 | 0.97 | 0.99 | 0.93 | 0.94 | 0.96 | 0.99 |
| . | IDA v ACD . | IDA + COMBI v ACD . | COMBI v ACD . | |||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| . | Ferritin . | TfR . | TfR × 100/Ferritin . | TfR-F Index . | Ferritin . | TfR . | TfR × 100/Ferritin . | TfR-F Index . | Ferritin . | TfR . | TfR × 100/Ferritin . | TfR-F Index . |
| False negative | 1 | 3 | 1 | 0 | 6 | 4 | 3 | 1 | 5 | 1 | 2 | 1 |
| False positive | 1 | 4 | 1 | 0 | 1 | 4 | 1 | 0 | 1 | 4 | 1 | 0 |
| True negative | 63 | 60 | 63 | 64 | 63 | 60 | 63 | 64 | 63 | 60 | 63 | 64 |
| True positive | 47 | 45 | 47 | 48 | 59 | 61 | 62 | 64 | 12 | 16 | 15 | 16 |
| Sensitivity | 0.98 | 0.94 | 0.98 | 1.00 | 0.91 | 0.94 | 0.95 | 0.98 | 0.71 | 0.94 | 0.88 | 0.94 |
| Specificity | 0.98 | 0.94 | 0.98 | 1.00 | 0.98 | 0.94 | 0.98 | 1.00 | 0.98 | 0.94 | 0.98 | 1.00 |
| Positive PV | 0.98 | 0.92 | 0.98 | 1.00 | 0.98 | 0.94 | 0.98 | 1.00 | 0.92 | 0.80 | 0.94 | 1.00 |
| Negative PV | 0.98 | 0.95 | 0.98 | 1.00 | 0.91 | 0.94 | 0.95 | 0.98 | 0.93 | 0.98 | 0.97 | 0.98 |
| Efficiency | 0.98 | 0.94 | 0.98 | 1.00 | 0.95 | 0.94 | 0.97 | 0.99 | 0.93 | 0.94 | 0.96 | 0.99 |
An efficiency curve for the distinction between ACD and IDA patients was generated for each parameter, and the maximum point of the curve was used as a cutoff limit in all patient populations. The cutoff limits based on the efficiency curves were 41 μg/L for ferritin, 2.7 mg/L for TfR, 4.5 for TfR × 100/ferritin, and 1.5 for the TfR-F Index. PV = predictive value.