❀ Shar‘i Ruling on Blood Tests While Fasting
Source: Fatāwā Arkan-e-Islam
✦ The Question
Does undergoing a blood test during fasting break the fast?
✦ Shar‘i Answer
Al-ḥamdu lillāh, waṣ-ṣalātu was-salāmu ʿalā Rasūlillāh, Ammā Baʿd!
✔ Taking a small amount of blood for medical testing during fasting does not invalidate the fast.
The explanation is provided below:
➊ Taking a Small Amount of Blood for Testing
❀ Blood is often withdrawn in small quantities for diagnostic purposes.
❀ This small amount does not weaken the body significantly, nor does it resemble cupping (ḥijāmah) in its effect.
❀ Hence, it does not break the fast.
➋ Foundational Principle
✔ The default Shar‘i principle is that a fast remains valid unless a clear proof exists that it has been nullified.
✔ In the case of a simple blood test, no such evidence exists to declare the fast broken.
➌ What About Donating a Large Amount of Blood?
✘ If a large amount of blood is taken from the fasting person—such as for blood donation—then:
❀ It carries the same effect as cupping,
❀ And therefore, breaks the fast according to many scholars.
Exception:
✔ Donating blood during fasting is only permitted if:
◈ The recipient is in a critical condition,
◈ Waiting until sunset is not possible,
◈ Medical professionals confirm that immediate donation is necessary to save a life or treat a severe condition.
➍ What to Do If the Fast Is Broken Due to Blood Donation?
❀ If a fasting person is compelled to donate a large amount of blood, and their fast is nullified:
✔ They may eat and drink afterward to regain strength.
✔ They must later make up (qadhā') for that day's fast.
✔ Summary:
| Situation | Ruling on the Fast |
|---|---|
 Small blood sample for test | Fast remains valid |
 Large amount of blood (donation) | Fast is broken |
| ⚠ Donation due to necessity | Allowed — with qadhā’ |
ھٰذَا مَا عِندِي وَاللّٰهُ أَعْلَمُ بِالصَّوَابِ
