Does Kidney Dialysis Break Your Fast?
Question

How should a person who suffers kidney failure and who has dialysis three times a week fast?
Praise be to Allah.Does kidney dialysis affect a person’s fast? 
The Standing Committee was asked: 
Does kidney dialysis affect a person’s fast? 
They replied: 
“We wrote to the Director of the King Faisal Specialist Hospital and the Director of the Armed Forces Hospital in Riyadh to find out more about what is involved in kidney dialysis and whether chemical substances are used, and whether it is regarded as a kind of nourishment. 
They replied as follows: 
(Kidney dialysis involves taking the patient’s blood into a machine (an artificial kidney) which cleans it then returns it to the body. It also adds some chemicals and nutrients such as sugars and salts etc. to the blood.) 
After studying the matter and discovering the nature of kidney dialysis with the help of some experts in the field, the Standing Committee issued a fatwa stating that kidney dialysis invalidates the fast. 
And Allah is the Source of strength. May Allah send blessings and peace upon our Prophet Muhammad and his family and Companions.” 
Shaykh Ibn ‘Uthaymin (may Allah have mercy on him) was asked about a person who undergoes kidney dialysis – does having his blood removed during the procedure invalidate his wudu? How should he fast and pray whilst having dialysis done, if that coincides with the time of prayer? 
He replied: 
Does kidney dialysis invalidate wudu?
“With regard to wudu, kidney dialysis does not invalidate wudu, because the correct scholarly view is that what comes out of the body does not invalidate wudu unless it comes out of either the front or back passage. Whatever comes out of those two passages invalidates wudu, whether it is urine, stools or wind. Everything that comes out of the two passages invalidates wudu. 
With regard to that which comes out of anywhere other than the two passages, such as a nosebleed that comes out of the nose, or blood that comes out of a wound, and so on, it does not invalidate wudu whether in small or large quantities. Based on this, kidney dialysis does not invalidate wudu. 
How can a person with kidney dialysis offer prayer?
With regard to prayer, the patient can join Zuhr and `Asr, and Maghrib and `Isha. He can plan his schedule with his doctor, to make sure that the dialysis will not take more than half the day, so that he will not miss praying Zuhr and `Asr on time. He can say to him, for example: Schedule the dialysis in the early afternoon, giving me enough time to pray Zuhr and `Asr, or bring it forward so that I will be able to pray Zuhr and `Asr (afterwards), before the time for `Asr ends. What matters is that it is permissible to combine the prayers without delaying them. Based on this it is essential to plan one’s schedule with one’s doctor. 
With regard to fasting, we are not sure about that. Sometimes I would say that it is not like cupping, because with cupping blood is taken and not returned to the body, and this invalidates the fast as it says in the hadith. 
In dialysis, the blood is taken from the body, cleaned and returned to the body. But I am concerned that dialysis involves some nutrients which take the place of food and drink. If that is the case, then it does invalidate the fast. In that case, if this is a lifelong condition with no hope of recovery, then he should feed one poor person for each day. But if it happens intermittently, then he should not fast when he is undergoing dialysis and make up that day later on. 
But if the substances that are mixed with the blood do not include nutrients, rather they simply cleanse the blood, then this does not break the fast. In this case, he may use dialysis even if he is fasting. He should refer to the doctors about this matter.” (Majmu’ Fatawa Ibn ‘Uthaymin, 20/113) 
In conclusion, a person who is suffering from kidney failure should not fast on the days when he has dialysis, then if he can make up the fast he should do so. If he cannot make up the fasts because he is elderly and cannot fast, then he should not fast and should feed one poor person for each day.
And Allah knows best.