About blood test. About her condition?

My mother has recently started sugar tablet that is gp 1 from 20 days because from past 25 days she has alterations in sugar levels when tested at home before and after meals values were like sometimes 160 ;180 like that so she immediately consulted a doctor through practo and she suggested to take gp1 tab for one month .my mom started taking these tablets.but doctor did not ask for any blood test like hba1c before giving prescription.i asked a question about my mother's condition about this on practo.doctors advised that ask her to test hba1c blood test.what my doubt is now she is in the under medication does she go for hba1c test during medication or after the completion of course?my mother did not went for any sugar tests previously.she has this condition since one month only.pls suggest us when does she go for hba1c test for complete idea about her condition? Pls help