Ref. No. 41/1078
In the name of Allah the most Gracious the most Merciful
The answer to your question is as follows:
If a patient is in critical condition and there is no option left except for blood transfusion then it is allowed to donate blood only as much as required. But the donor is not allowed to charge the patient for it. Moreover, donating organs of human beings is not allowed. It must be noted that all the organs of a human being are in full possession of Allah (swt) and they are not in his/her ownership in order that he/she can treat with them as they like. Human beings have no right to utilise them in accordance with his free will.
ولا يجوز بيع شعور الإنسان ولا الانتفاع بها" لأن الآدمي مكرم لا مبتذل فلا يجوز أن يكون شيء من أجزائه مهانا ومبتذلا )ہدایہ 3/46) کسر عظم المیت ککسرہ حیا (سنن ابی داؤد حدیث 3207)۔
And Allah knows best
Darul Uloom Waqf Deoband