Does Blood Donation Break Wudu?
Question

Can a Muslim donate blood, and if so can he offer prayer straight after donating blood?
Praise be to Allah.Is blood donation halal?
If it is necessary to carry out a blood transfusion , there is no sin on the patient, the doctors or the donor, because of the following:
1.      Allah says (interpretation of the meaning): “… and if anyone saved a life, it would be as if he saved the life of all mankind…” [al-Maidah 5:32]. 
This verse indicates the virtue of being the cause of saving the life of someone whom it is forbidden to kill, and there is no doubt that the doctors and blood donors are among the causes of saving the life of patients who are at risk of dying if a blood transfusion is not carried out.
2.                Allah says (interpretation of the meaning): “He has forbidden you only the dead animals, and blood, and the flesh of swine, and that which is slaughtered as a sacrifice for other than Allah. But if one is forced by necessity without wilful disobedience nor transgressing due limits, then there is no sin on him. Truly, Allah is Oft-Forgiving, Most Merciful.” [al-Baqarah 2:173]. 
This verse indicates that there is no sin on the one who does a forbidden thing out of necessity; the sick person accepts a blood transfusion out of necessity, and there is nothing wrong with the donor giving his blood either.
3.                The guidelines of Islamic Shari`ah dictate that donating blood should be permitted, because one of its principles is that in cases of necessity, things that are ordinarily forbidden are permitted, and that ways should be found to ease hardship. The sick person is certainly in a hardship situation, and is compelled by necessity. The hardship he is facing could lead to his death, so it is permissible for him to receive a blood transfusion. (For more details on the issue of donating blood, please see Question #2570 ).
Does blood donation break wudu?
As regards the question of whether wudu is broken by the flowing of blood, this is an issue concerning which the scholars, may Allah have mercy on them, differed. Those who think that bleeding breaks wudu quote as evidence the hadith of Abu’l-Darda (may Allah be pleased with him): “The Prophet (peace and blessings of Allah be upon him) vomited, then did wudu.” They drew an analogy between vomit and blood, because both are najis (impure) when they come out of the body.
This hadith was narrated by Ahmad (4/449), Abu Dawud (2981) and al-Tirmidhi (87), who said: “More than one of the scholars among the Companions of the Prophet (peace and blessings of Allah be upon him) and others among the Tabi’in thought that wudu should be done after vomiting or having a nosebleed. This is the opinion of Sufyan al-Thawri, Ibn al-Mubarak, Ahmad and Ishaq. Some scholars said that wudu is not necessary after vomiting or having a nosebleed. This is the opinion of Malik and al-Shafi’i.” This was also narrated as being the opinion of Ahmad. Al-Baghawi said: It is the opinion of most of the Sahabah and Tabi’in.”
The most correct view is that bleeding does not break one’s wudu, although it is preferable (mustahabb) to make wudu after bleeding. The evidence for this is as follows:
1.      Wudu is considered to be valid until there is proof that something breaks it. There is no proof narrated from the Prophet (peace and blessings of Allah be upon him) that bleeding breaks wudu , hence Imam al-Nawawi (may Allah have mercy on him) said, “There is no proof whatsoever that the Prophet (peace and blessings of Allah be upon him) made it obligatory to do wudu because of that (bleeding).” Shaykh Ibn Sa’di (may Allah have mercy on him) said, the correct opinion is that bleeding and vomiting , etc., do not break wudu, whether they are large or small in volume, because there is no evidence to prove that they break wudu, and the guiding principle is that wudu remains valid.
2.      One cannot draw an analogy between blood and anything else, because the reasons behind them are not the same.
3.      The idea that bleeding breaks wudu is contrary to what was reported from the salaf (early generations), for example, ‘Umar ibn al-Khattab (may Allah be pleased with him) continued to pray although his wound was pouring with blood. Al-Hasan al-Basri (may Allah have mercy on him) said, “The Muslims continue to pray even when they are wounded.”
4.      The fact that the Prophet (peace and blessings of Allah be upon him) did wudu after he vomited does not indicate that it is obligatory to do so, because the rules of fiqh say that the mere fact that he did something, unless it was accompanied by a command to do it, does not make it obligatory. All that this proves is that it is good to follow the example of the Prophet (peace and blessings of Allah be upon him) in this instance. Hence Shaykh al-Islam Ibn Taymiyah (may Allah have mercy on him) said: “Doing wudu after cupping and vomiting is mustahabb and is good.”
To sum up the above, it is mustahabb (preferable) for a blood donor to do wudu after giving blood, but if he does not do wudu, it is still OK.
And Allah knows best.
On the issue of donation, please see:
·        Al-Mukhtaraat al-Jaliyyah by Shaykh ‘Abd al-Rahman ibn Sa’di, 327; 
·        Ahkam al-At’imah fi’l-Shari’ah by Dr. ‘Abd-Allah al-Tariqi, 411, 
·        Majallat al-Majma’ al-Fiqhi, issue 1, p. 32; 
·        Naql al-Damm wa Ahkamuhu by al-Safi, 27; 
·        Ahkam al-Jirahah al-Tibbiyah, by Dr. al-Shanqiti, 580.
On the issue of bleeding breaking wudu, please see:
·        Majmu’ al-Fatawa, 20/526; 
·        Sharh ‘Umdat al-Fiqh, by Ibn Taymiyah, 1/295; 
·        al-Mughni by Ibn Qudamah, 1/234; 
·        Tawdih al-Ahkam by al-Bassam, 1/239; 
·        al-Sharh al-Mumti’ by Ibn ‘Uthaymin, 1/221.