Table 1 Overview of recommendations for field evaluation of quantitative G6PD assays

Sample size for performance evaluation

Two approaches, based on:

• Desired performance indicators

• Minimal difference in means measured by two methods

[51, 52]

Sample size WHO pre-qualification

• 200 G6PD specimens

• 200 G6PD intermediate specimens

• 1000 G6PD normal specimens

[34]

Sample

Venous or capillary blood

[40, 41]

Max time to reference testing

4–7 days

[35,36,37,38]

Sample storage temperature

At 4–8 °C

[35,36,37,38]

Reference testing

Spectrophotometry

[24, 42]

Statistical methods

• Bland–Altman plot

• Scatter plot

• Histogram of G6PD activity distribution/test assay

• ROC analysis

• Adjusted male median

• Sensitivity, specificity, positive and negative predictive value

[24, 55, 56]