Question Summary:
I m a diabetec patient.is it permisseble during fast to check sugar through my blood?can i have my insulin injection before breaking a fast?

Question Detail:

i m a diabetec patient.is it permisseble during fast to check sugar through my blood?can i have my insulin injection before breaking a fast?

Answer :

In the name of Allah, Most Gracious, Most Merciful
Assalaamu `alaykum waRahmatullahi Wabarakatuh
It is permissible to withdraw some blood to check for sugar while fasting.  It is also permissible to take an insulin injection while fasting, as long as it is not taken directly into the stomach. 
However, you should consult a Muslim doctor on whether it is advisable for you to fast or not.
وفي الجائفة والآمة إذا داواهما بدواء يابس لا يفسد صومه وإذا داواهما بدواء رطب يفسد صومه عند أبي حنيفة خلافا لهما وأكثر المشايخ اعتبر الوصول إلى الجوف
(المحيط البرهاني، كتاب الصوم، الفصل الرابع: 3/348؛ إدارة)
 
(جديد فقهي مسائل، عبادات، روزه: 1/179-182؛ نعيميه)
 
And Allah knows best
Wassalaamu `alaykum
Ml. Abrar Mirza,
Student Darul Iftaa
Darul Iftaa, Madrassah In'aamiyyah