Comparing G6PD Tests Using Capillary Blood Versus Venous Blood

Study Overview
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Brief Summary
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In this study we propose to determine the correlation in glucose-6phosphate dehydrogenase enzyme activity in capillary blood obtained from a finger stick versus a venous blood specimen. As secondary endpoints we will seek to correlate phenotype as determined by quantitative and qualitative G6PD test, genotype as determined by PCR and DNA sequencing with flow cytometry. The secondary endpoints are critical for the design of G6PD diagnostic test evaluation studies.

Detailed Description
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In this study we propose to determine the correlation in glucose-6 phosphate dehydrogenase enzyme activity in capillary blood obtained from a finger stick versus a venous blood specimen. We will also compare results of different G6PD tests with known G6PD genetic profiles. The results of the study will inform design of future G6PD diagnostic development & evaluations. This research will be conducted in MaeSot Thailand, where G6PD deficiency has a high prevalence. Study participants will be recruited into three groups of 50 volunteers per group: 50 G6PD-deficient individuals, 50 G6PD-normal individuals, and 50 G6PD-intermediate individuals. Following a written informed consent, participants will donate about 3 ml of venous blood and about 4 drops of capillary blood (fingerstick). There will be no direct benefit to research participants.

Official Title
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Correlation of G6PD Activity Across Different Sample Sources, and Different G6PD Testing Platforms

Conditions
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Glucose-6 Phosphate Dehydrogenase Deficiency

Intervention / Treatment
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* Other: G6PD Test


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Previous G6PD test at SMRU clinic Patient willing to participate and sign informed consent form Patient willing to allow donated sample to be used in future research Subjects 18 years of age or older Exclusion Criteria: patients with severe malaria or other severe illness Patients who received a blood transfusion in the last 3 months Patients who received primaquine in the past 1 month (this is to ensure that previous characterization of phenotype in the healthy subject has not been influenced by a recent hemolytic reaction)

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Diagnostic
Intervention Model: Single Group Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| No Intervention: G6PD Testing<br>All subjects receive G6PD test | Other: G6PD Test<br>* All subjects are tested by multiple G6PD tests<br>* Other names: Florescent Spot Test;|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Correlation of capillary and venous blood results using Trinity quantitative G6PD test | Comparison of the performance of the Trinity quantitative test using capillary blood, vs the performance of the same test using venous blood. | Six months | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Concordance between a flow cytometry-based G6PD test and the spectrophotometric gold standard | Percent agreement between the quantitative results of the flow cytometry assay and the quantitative results of the spectrophotometric assay. | six months | 
| Categorical accuracy of a flow cytometry-based G6PD test against the spectrophotometric gold standard and genotyping | Using a predefined cutoff to categorize values from each quantitative test, determine percent agreement within each category between the two tests. | six months | 
| Concordance between a qualitative G6PD test and the spectrophotometric gold standard | Compare sensitivity & specificity of qualitative results of the G6PD test and the categorical results of the quantitative spectrophotometric assay. | Six months | 
| Categorical accuracy of qualitative G6PD test against spectrophotometric gold standard | Percent agreement between the qualitative G6PD test and the categorical results of the spectrophotometric gold standard | six months | 
| Association between flow cytometry-based test and sample genotype | Determine accuracy of phenotypic results of flow cytometry assay against genetic profile. | Six months | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Glucose-6 phosphate dehydrogenase deficiency, capillary, venous, genotype phenotype correlation