A novel point-of-care device for measuring glucose-6-phosphate dehydrogenase enzyme deficiency

Preliminary Investigation into the Prevalence of G6PD Deficiency in a Pediatric African American Population Using a Near-Patient Diagnostic Platform

Glucose-6-phosphate dehydrogenase (G6PD) deficiency is prevalent in the African American population. We identified eighteen G6PD-deficient samples (9%) in a study of residual, de-identified whole blood specimens from 200 African American pediatric patients using a point-of-care instrument. This highlights the possibility of a rapid time to result for G6PD testing, which can be valuable in some clinical scenarios.

Technical evaluation and usability of a quantitative G6PD POC test in cord blood: a mixed-methods study in a low-resource setting

OBJECTIVES

New point-of-care (POC) quantitative G6PD testing devices developed to provide safe radical cure for Plasmodium vivax malaria may be used to diagnose G6PD deficiency in newborns at risk of severe neonatal hyperbilirubinaemia, improving clinical care, and preventing related morbidity and mortality.

METHODS

We conducted a mixed-methods study analysing technical performance and usability of the 'STANDARD G6PD' Biosensor when used by trained midwives on cord blood samples at two rural clinics on the Thailand-Myanmar border.

RESULTS

In 307 cord blood samples, the Biosensor had a sensitivity of 1.000 (95% CI: 0.859 to 1.000) and a specificity of 0.993 (95% CI: 0.971 to 0.999) as compared with gold-standard spectrophotometry to diagnose G6PD-deficient newborns using a receiver operating characteristic (ROC) analysis-derived threshold of ≤4.8 IU/gHb. The Biosensor had a sensitivity of 0.727 (95% CI: 0.498 to 0.893) and specificity of 0.933 (95% CI: 0.876 to 0.969) for 30%-70% activity range in girls using ROC analysis-derived range of 4.9-9.9 IU/gHb. These thresholds allowed identification of all G6PD-deficient neonates and 80% of female neonates with intermediate phenotypes.Need of phototherapy treatment for neonatal hyperbilirubinaemia was higher in neonates with deficient and intermediate phenotypes as diagnosed by either reference spectrophotometry or Biosensor.Focus group discussions found high levels of learnability, willingness, satisfaction and suitability for the Biosensor in this setting. The staff valued the capacity of the Biosensor to identify newborns with G6PD deficiency early ('We can know that early, we can counsel the parents about the chances of their children getting jaundice') and at the POC, including in more rural settings ('Because we can know the right result of the G6PD deficiency in a short time, especially for the clinic which does not have a lab').

CONCLUSIONS

The Biosensor is a suitable tool in this resource-constrained setting to identify newborns with abnormal G6PD phenotypes at increased risk of neonatal hyperbilirubinaemia.

Thirty-five males with severe (Class 1) G6PD deficiency (c.637G>T) in a North American family of European ancestry

In North America, jaundiced neonates are not usually tested for G6PD deficiency if the family is of European ancestry. However, we describe such a family where ≥35 males have had severe (Class I) G6PD deficiency. Many of the jaundiced neonates did not have this diagnosis considered, at least three of whom developed bilirubin neurotoxicity. Over seven generations 35 affected males were identified. Three developed signs of kernicterus spectrum disorder; three had exchange transfusions for hyperbilirubinemia; and nine received one or more blood transfusions during childhood.

Reference and point-of-care testing for G6PD deficiency: Blood disorder interference, contrived specimens, and fingerstick equivalence and precision

Certain clinical indications and treatments such as the use of rasburicase in cancer therapy and 8-aminoquinolines for Plasmodium vivax malaria treatment would benefit from a point-of-care test for glucose-6-phosphate dehydrogenase (G6PD) deficiency. Three studies were conducted to evaluate the performance of one such test: the STANDARD^™ G6PD Test (SD BIOSENSOR, South Korea). First, biological interference on the test performance was evaluated in specimens with common blood disorders, including high white blood cell (WBC) counts. Second, the test precision on fingerstick specimens was evaluated against five individuals of each, deficient, intermediate, and normal G6PD activity status. Third, clinical performance of the test was evaluated at three point-of-care settings in the United States. The test performed equivalently to the reference assay in specimens with common blood disorders. High WBC count blood samples resulted in overestimation of G6PD activity in both the reference assay and the STANDARD G6PD Test. The STANDARD G6PD Test showed good precision on multiple fingerstick specimens from the same individual. The same G6PD threshold values (U/g Hb) were applied for a semiquantitative interpretation for fingerstick- and venous-derived results. The sensitivity/specificity values (95% confidence intervals) for the test for G6PD deficiency were 100 (92.3–100.0)/97 (95.2–98.2) and 100 (95.7–100.0)/97.4 (95.7–98.5) for venous and capillary specimens, respectively. The same values for females with intermediate (> 30% to ≤ 70%) G6PD activity were 94.1 (71.3–99.9)/88.2 (83.9–91.7) and 82.4 (56.6–96.2)/87.6(83.3–91.2) for venous and capillary specimens, respectively. The STANDARD G6PD Test enables point-of-care testing for G6PD deficiency.

Economic evaluation of point of care universal newborn screening for glucose-6-Phosphate dehydrogenase deficiency in United States

BACKGROUND AND OBJECTIVES

Glucose-6-Phosphate Dehydrogenase (G6PD) deficiency is frequent inherited enzymopathy that poses potentially preventable risk for extreme hyperbilirubinemia (EHB) which can, rarely, lead to acute bilirubin encephalopathy, childhood kernicterus and death. We aimed to estimate quality adjusted life years (QALY) lost due to G6PD deficiency associated with EHB and economic costs to best estimate value of universal pre-discharge screening.

METHODS

We did a cost utility analysis for US birth cohort utilizing pre-discharge screening decision tree model to estimate population burden and EHB outcomes, based on literature search and expert opinions. Employing human capital approach, we measured health benefits in terms of QALYs and economic losses. QALYs and costs were discounted at 3%; one-way sensitivity analysis was used for decision variables.

RESULTS

We determined for USA live births of 3.86 million in 2017, 1464 cases of EHB were estimated to be due to G6PD deficiency (CI 95%; range: 1270-1656) and contributed 2 deaths (CI 95%; range 1.3-3.2) and 14 (CI 95%; range: 9.1-21.5) cases of kernicterus. Over lifetime horizon, the model predicted undiscounted and discounted gains of 165 (102-252) life years; 241 (183-433) QALYs and 16 (9.9-24.5) life years; 89 (67.9-160.5) QALYs, respectively. Assuming 50% effectiveness, benefit cost ratios ranged from 0.19 to 3.42 for diverse operational settings. The cost to prevent a single case of kernicterus was $2.7 to 6.8 million per annum with cost per QALY gained at $35,946 to $89,159.

CONCLUSION

At incremental cost-effective threshold of $100,000/life year, pre-discharge screening would be expected to prove cost effective in preventing EHB related morbidities and mortality attributed to G6PD deficiency.