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Background Measurement of glucose-6-phosphate dehydrogenase (G6PD) activity guides hypnozoitocidal treatment of P vivax malaria. The G6PD Standard (SDBiosensor, Republic of Korea) here referred to as “Biosensor” is a quantitative point-of-care diagnostic that measures G6PD activity in U/gHb. The manufacturer recommends cutoffs to define G6PD deficient (≤ 4.0U/gHb), intermediate (4.1- ≤ 6.0U/gHb) and normal (> 6.0U/gHb) individuals. The aim of this individual patient data (IPD) meta-analysis was to evaluate these cutoffs (CRD42023406595). Methods A systematic review identified studies reporting population-level G6PD activity measured by Biosensor, published between January 2017 and May 2023. IPD were collated and standardised. The adjusted male median (AMM) was defined as 100% activity and calculated across all studies (universal AMM) and separately for each setting. The proportion of participants classified as deficient or intermediate were compared using the manufacturer-recommended cutoffs and 30% and 70% of the universal AMM and setting-specific AMM. Associations between G6PD activity and blood sampling method, malaria status, and age were assessed. Results Eleven studies with 9724 participants from eight countries were included in this analysis. The universal AMM was 7.7U/gHb and the setting-specific AMMs ranged from 6.2U/gHb to 9.9U/gHb. When using the universal AMM, 4.2% of participants were classified as deficient and 11.9% as intermediate or deficient. The corresponding values were 3.9% and 10.8% for setting-specific cutoffs, and 7.2% and 18.3% for manufacturer-recommended definitions for deficients and intermediates respectively. The manufacturer-recommended cutoff for deficient individuals fitted the distribution of G6PD activities better than definitions based on the percentage of AMM. There was no significant association between malaria status or blood sampling method and G6PD activity. Measured G6PD activity decreased in children 1–5 years and plateaued thereafter. Conclusion The manufacturer’s recommended cutoff is conservative but more reliable at categorising G6PD deficient individuals than those based on calculations of 30% activity using the AMM. The observed decrease in G6PD activity in children between 1 and 5 years of age warrants further investigation.

Background: Glucose-6-phosphate dehydrogenase (G6PD) deficiency testing is not routinely performed before primaquine treatment in most Plasmodium vivax endemic areas, despite the risk of primaquine-associated hemolysis. This is due to the operational challenges associated with pragmatic G6PD testing and as such needs to be addressed. Methods and findings: This mixed-methods operational study was aimed at implementing the quantitative point-of-care StandardTM G6PD (SD Biosensor, Korea) screening test in malaria treatment units (MTUs) in the municipalities of Rio Preto da Eva and Mâncio Lima, in the Brazilian Amazon, between mid-January 2020 and December 2020. In total, 1286 P. vivax cases were treated based on the Standard G6PD test: 1230 had activity equal to or greater than 4.0 U/g Hb, and 56 less than 4.0 U/g Hb. No G6PD deficient (G6PDd) genotypes were found in 96 samples from the 1230, and only 21 of the 56 G6PDd cases had confirmed G6PDd genotypes. Evaluations were conducted on the proficiency of health care professionals (HCPs) training to perform the test, the reliability of testing performed in the field, and the perceptions of HCPs and patients about the implementation. Post-training proficiency was 73.4% after a 4-hour training session. This study revealed that locations with lower malaria caseloads will need regular refresher training. The test was well accepted by both HCPs and patients. Signs and symptoms of hemolysis were not always associated with malaria treatment drugs by HCPs and patients. Interpretation: Point-of-care quantitative G6PD testing can be performed at MTUs in the Brazilian Amazon to inform treatment decisions with primaquine. Limitations related to technical and cultural aspects need to be addressed further when expanding screening to larger areas.

Background Glucose-6-Phosphate Dehydrogenase deficiency (G6PDd) is a common genetic enzymopathy that can induce haemolysis triggered by various factors, including some anti-malarial drugs. Although many Point-of-Care (PoC) tests, such as Standard G6PD™ are available to detect G6PDd, its pooled diagnostic test accuracy (DTA) remains unknown. Methods To estimate the DTA of StandG6PD-BS at various thresholds of G6PDd, a systematic review with a DTA meta-analysis were conducted, searching EMBASE, MEDLINE, and SciELO databases up to April 4, 2024.The included studies were those that measured G6PD activity using StandG6PD-BS (reference test) and spectrophotometry (gold standard) in patients suspected of having G6PDd. The risk of bias (RoB) of the studies was assessed using the QUADAS-2 tool and the certainty of evidence (CoE) with the GRADE approach. For the estimation of within-study DTA, a random-effect bivariate meta-analysis was performed to determine the pooled sensitivity and specificity for 30%, 70%, and 80% enzyme levels’ thresholds, and a graphical analysis of the heterogeneity using crosshair and Confidence Regions on receiver operating characteristic (ROC) space plots. Results After screening 2496 reports, four studies were included with 7864 participants covering all thresholds. Two studies had high RoB in QUADAS-2 domains 2 and 3, and the others had low RoB, with low, moderate, and high heterogeneity at the 30%, 70%, and 80% thresholds, respectively. The pooled sensitivity was 99.1%, 95.7%, and 90% for 30%, 70%, and 80% thresholds, respectively. The pooled specificity was 97.4%; 92.9%; and 89.0% for 30%, 70%, and 80% thresholds, respectively. Conclusion StandG6PD-BS is a PoC test with high sensitivity and specificity to detect G6PDd at different thresholds.

Objectives Spectrophotometry kits from Pointe Scientific (PS; USA) were compared to kits from Trinity Biotech (Trinity; Ireland) in 50 venous blood samples from purposively selected individuals in Bangladesh. Repeatability and inter-assay variability were assessed by Students t-test, Bland-Altman plot and Pearson correlation coefficient (r). The median glucose-6-phosphate dehydrogenase (G6PD) activity of all G6PD normal participants was calculated per assay and defined as 100% activity. Performance was calculated considering 30% and 70% cut off activities and Trinity as reference. Results The intra-assay correlation of Trinity (r = 0.9841, p < 0.001) and PS (r = 0.9833, p < 0.001) did not differ significantly (p = 0.904). Both assays were closely correlated (r = 0.9799, p < 0.001), with a mean difference of 0.1 U/gHb (95% limit of agreement: − 1.32 to 1.57). At 30% cut off PS had a sensitivity of 100% (95% confidence interval (95 CI) 59.0–100.0) and specificity of 100% (95% CI 91.8 to 100.0), at 70% cut-off of 100% (95% CI 79.4–100.0) and 97.1% (95% CI 84.7–99.9) respectively. The G6PD assay from PS is a reliable alternative to the assay from Trinity.

The only currently available drug that effectively removes malaria hypnozoites from the human host is primaquine. The use of 8-aminoquinolines is hampered by haemolytic side effects in glucose-6-phosphate dehydrogenase (G6PD) deficient individuals. Recently a number of qualitative and a quantitative rapid diagnostic test (RDT) format have been developed that provide an alternative to the current standard G6PD activity assays. The WHO has recently recommended routine testing of G6PD status prior to primaquine radical cure whenever possible. A workshop was held in the Philippines in early 2015 to discuss key challenges and knowledge gaps that hinder the introduction of routine G6PD testing. Two point-of-care (PoC) test formats for the measurement of G6PD activity are currently available: qualitative tests comparable to malaria RDT as well as biosensors that provide a quantitative reading. Qualitative G6PD PoC tests provide a binomial test result, are easy to use and some products are comparable in price to the widely used fluorescent spot test. Qualitative test results can accurately classify hemizygous males, heterozygous females, but may misclassify females with intermediate G6PD activity. Biosensors provide a more complex quantitative readout and are better suited to identify heterozygous females. While associated with higher costs per sample tested biosensors have the potential for broader use in other scenarios where knowledge of G6PD activity is relevant as well. The introduction of routine G6PD testing is associated with additional costs on top of routine treatment that will vary by setting and will need to be assessed prior to test introduction. Reliable G6PD PoC tests have the potential to play an essential role in future malaria elimination programmes, however require an improved understanding on how to best integrate routine G6PD testing into different health settings.

Background: Anaemia in pregnancy is typically due to iron deficiency (IDA) but remains a complex and pervasive problem, particularly in low resource settings. At clinics on the Myanmar-Thailand border, a protocol was developed to guide treatment by health workers in antenatal care (ANC). Objective: To evaluate the clinical use of a protocol to treat anaemia in pregnancy. Methods: The design was a descriptive retrospective analysis of antenatal data obtained during the use of a standard anaemia treatment protocol. Two consecutive haematocrits (HCT) <30% prompted a change from routine prophylaxis to treatment doses of haematinics. Endpoints were anaemia at delivery (most recent HCT before delivery <30%) and timeliness of treatment initiation. Women whose HCT failed to respond to the treatment were investigated. Results: From August 2007 to July 2012, a median [IQR] of five [4-11] HCT measurements per woman resulted in the treatment of anaemia in 20.7% (2,246/10,886) of pregnancies. Anaemia at delivery was present in 22.8% (511/2,246) of treated women and 1.4% (123/8,640) who remained on prophylaxis. Human error resulted in a failure to start treatment in 97 anaemic women (4.1%, denominator 2,343 (2,246 + 97)). Fluctuation of HCT around the cut-point of 30% was the major problem with the protocol accounting for half of the cases where treatment was delayed greater than 4 weeks. Delay in treatment was associated with a 1.5 fold higher odds of anaemia at delivery (95% CI 1.18, 1.97). Conclusion: There was high compliance to the protocol by the health workers. An important outcome of this evaluation was that the clinical definition of anaemia was changed to diminish missed opportunities for initiating treatment. Reduction of anaemia in pregnancy requires early ANC attendance, prompt treatment at the first HCT <30%, and support for health workers.

Objective: The purpose of this study was to analyze a targeted screening program for glucose-6-phosphate dehydrogenase (G6PD) deficiency (G6PDdef) and clinical outcomes of G6PD-deficient vs G6PD normal newborns. Study Design: Retrospective chart review for 1578 male newborns was performed. The study group was those screened for G6PDdef. Comparisons between G6PD-deficient and normal infants were made with χ 2 -test and unpaired t -test. Result: A total of 1095 male newborns were screened, 11.1% had G6PDdef. 97.8% of screen results were reported by 48 h. Total bilirubin (TB) levels in deficient infants were significantly higher than in normal infants throughout birth hospitalization and they were more likely to receive phototherapy. Nineteen screened newborns were rehospitalized for hyperbilirubinemia, 47% had G6PDdef. Conclusion: In-hospital newborn screening for G6PDdef with rapid turnaround time is possible. G6PDdef is a risk factor for hyperbilirubinemia in American newborns. US centers with large at-risk populations can identify newborns at risk for severe hyperbilirubinemia with similar screening.