2.5. Measurement of IMA
Plasma and PF IMA levels were analyzed using the colorimetric method developed by Bar-Or et al.30 In the basic principle of the test, 50 µL of cobalt chloride reagent is added to 200 µL of plasma/PF. The mixture is incubated for 10 minutes to form the albumin-cobalt complex. Then, 50 µL (1.5 mg/mL) of dithiothreitol solution is added as a coloring agent and vortexed. Finally, 1.0 mL of 0.9% NaCl is added. The colored complex formed by the addition of NaCl is measured spectrophotometrically at a wavelength of 470 nm. Results are expressed in absorbance units (ABSU).