Table 2.
Characteristics of 75 Female Patients Suspected to Have Heterozygous G6PD Deficiency as Detected by Genotyping, Related to G6PD Activity, G6PD:GR Activity Ratio, Chromate Inhibition, and Cytofluorometry.
| No Deficiency Number of Patients (%) | Heterozygous Deficiency Number of Patients (%) | Total Number of Patients (%) | Sensitivity (95% Confidence Interval) | Specificity (95% Confidence Interval) | |
|---|---|---|---|---|---|
| Spectrophotometry | |||||
| G6PD < 3.8 IU/g Hb (deficient) | 0 (0.0) | 14 (18.7) | 14 (18.7) | 0.52 [0.32, 0.71] | 1.00 [0.93, 1.00] |
| G6PD ≥ 3.8 IU/g Hb (normal) | 48 (64.0) | 13 (17.3) | 61 (81.3) | ||
| G6PD:GR < 0.46 (deficient) | 0 (0.0) | 3 (4.0) | 3 (4.0) | 0.96 [0.81, 1.00] | 0.19 [0.09, 0.33] |
| G6PD:GR 0.46 – 0.9 (intermediate) | 39 (52) | 23 (30.7) | 62 (82.7) | ||
| G6PD:GR > 0.9 (normal) | 9 (12.0) | 1 (1.3) | 10 (13.3) | ||
| Chromate inhibition | |||||
| Chromate > 2.0 IU/g Hb (deficient) | 1 (1.3) | 25 (33.3) | 26 (34.7) | 0.96 [0.71, 1.00] | 0.98 [0.89, 1.00] |
| Chromate 1.7 – 2.0 IU/g Hb (intermediate) | 0 (0.0) | 1 (1.3) | 1 (1.3) | ||
| Chromate < 1.7 IU/g Hb (normal) | 47 (62.7) | 1 (1.3) | 48 (64.0) | ||
| Cytofluorometry | |||||
| Cytofluorometry > 10.15% (deficient) | 6 (8.0) | 23 (30.7) | 29 (38.7) | 0.85 [0.66, 0.96] | 0.88 [0.75, 0.95] |
| Cytofluorometry < 10.15% (normal) | 42 (56) | 4 (5.3) | 46 (61.3) | ||
Sensitivity of chromate inhibition and G6PD:GR ratio was calculated after combination of the intermediate group and the deficient group as one group. Abbreviations: G6PD, glucose-6-phosphate dehydrogenase; GR, glutathione reductase; IU g/Hb, international units per gram hemoglobin.