Validation of New G6PD Point of Care Tests Against Gold Standard Quantitative

Study Overview
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Brief Summary
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This is a laboratory research to evaluate performances of quantitative POC G6PD tests (Biosensors) against gold standard quantitative laboratory based tests and genotyping.

Detailed Description
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Radical cure of P. vivax malaria can be achieved using large doses of primaquine which have shown to cause some degree of hemolysis even in subjects who tested normal by the conventional qualitative G6PD tests. Different regimens of drug might be more appropriate in subjects with intermediate G6PD activity which can be currently measured only in well equipped laboratories. Validation of new qualitative and quantitative point-of-care tests is essential to for safe deployment of standard and new radical cure regimens against Plasmodium vivax. This study will evaluate performances of quantitative POC G6PD tests (Biosensors) against gold standard quantitative laboratory based tests and genotyping. Patients will be searched from the electronic record database to identify up to 150 patients with the following characteristics: approximately 50 G6PD-deficient men and women (however only a very small percent of deficients are homozygous women) approximately 50 G6PD-heterozygous women with intermediate activity, and approximately 50 G6PD-normal individuals and patients who meet the screening criteria will be contacted at their home by a clinic staff member. The home visitor will explain study details and invite to participate in the study. If the patients express interest in participating, they will be directed to visit the following month at the clinic where they usually receive care. After signing the informed consent form, two blood samples will be withdrawn; one sample will be taken by finger-stick (200 µl) and one sample (0.5 ml) will be taken by arm venipuncture. The blood from capillary sample will be used to assess G6PD activity using the POC tests, CBC and laboratory based quantitative tests. The venous blood will be used for reference standard quantitative G6PD assays, Hb typing analysis, CBC and buffy-coat will be stored for DNA extraction for G6PD genotyping only; leftover blood will be discarded.

Official Title
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Validation of New G6PD Point of Care Tests (Biosensors) Against Gold Standard Quantitative Spectrophotometry and Genotyping

Conditions
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Validation, Biosensors, Genotyping

Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Subjects with age ≥ 18 years Subjects willing to participate and sign informed consent form Male and Female Previously tested G6PD deficient, G6PD normal and G6PD intermediate or heterozygous for G6PD variants at SMRU clinic Exclusion Criteria: Patients with severe malaria or other severe or any acute 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) Patients who have not had a critical illness or received other hemolytic drugs (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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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| G6PD Deficient Volunteers<br>Subjects with age ≥ 18 years Male and female Previously tested G6PD deficient at SMRU clinic | |
| G6PD Intermediate or Heterozygous Volunteers<br>Subjects with age ≥ 18 years Female Previously tested G6PD intermediate or heterozygous for G6PD variants at SMRU clinic | |
| G6PD-Normal Volunteers<br>Subjects with age ≥ 18 years Male and female Previously tested G6PD normal at SMRU clinic | |

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| correlation in G6PD activity | determined by the Biosensors and the spectrophotometric gold standard. | at enrollment | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| correlation in Hemoglobin levels | determined by the Biosensors and the automated blood analyzer. | at enrollment | 
| Determine association between one or more quantitative POC G6PD test (Biosensor) and the flow cytometry-based G6PD test |  | at enrollment |