Kidney Function and Prediabetes — Tisha B’Av
Question
**Subject:** Practical halachic question — the fast of Tisha B’Av for a 14-year-old boy with a medical background
To the honored rabbis of the Beit Hora’ah, shlita,
We would like to ask regarding the obligation to fast on Tisha B’Av this year for my 14-year-old son.
In recent laboratory tests (dated 02/06/2026), the following findings appeared, and the treating physician noted that they indicate an issue requiring caution:
1. **Kidney function (creatinine):** The blood creatinine level is **0.8~mg/dL** (with the upper limit of the normal range shown as 0.94). The treating physician emphasized that this finding indicates a problem and that great caution is necessary.
2. **Concern for prediabetes:** The HbA1C value is **5.6%** (defined on the form as an increased risk for prediabetes beginning at 5.7%). The fasting glucose value is **90~mg/dL**.
**Our questions are:**
1. In light of the doctor’s concern about kidney function and the danger of dehydration, is the boy completely exempt from fasting this year, or should he begin fasting and break the fast if he does not feel well?
2. If there is an exemption, should he eat and drink normally (because of the concern regarding the kidneys and prediabetes), or is there a point in eating and drinking “le-shiurim” (less than the halachic measure at a time)?
We would appreciate your clear halachic guidance.
With blessings of Torah and many thanks,
Answer
Shalom u’vrachah
He may eat and drink as usual.
