Abstract
In the present study we tried to determine whether dry blood samples spotted on a sheet of filter paper could be used to measure HbA1c. Blood samples obtained by fingerprick were spotted on filter paper and arrived in our laboratory three days after being mailed. HbA1c was measured by turbidimetric inhibition immunoassay (TINIA) using hemolysates eluted from the spotted filter paper by immersing it in the hemolyzing solution. For comparison, HbA1c values were measured in fresh venous blood samples from the same subjects by HPLC, which was shown not to be feasible for measurement of HbA1c using hemolysates of dry blood samples.
Within-day and between-day precision of HbA1c measurements by TINIA yielded coefficients of variation of 1.22-1.99% and 2.32-3.81%, respectively. The HbA1c values of fresh venous bood samples measured by HPLC were well correlated with the values obtained using spotted fingerprick blood (r=0.975, p<0.001) and spotted venous blood samples (r=0.975, p<0.001) analyzed by TINIA.
In conclusion, mailed dry blood samples spotted on filter paper can be used to measure HbA1c by TINIA.
