Where should I take my 14-year-old's temperature when axillary reading is unreliable?

You can get an accurate core-body temperature with a simple oral or rectal reading. For a 14-year-old, recommended options:

1. Oral (best noninvasive choice)

   • Use a digital oral thermometer.
   • Wait 15–30 minutes after he has eaten, drunk, or been mouth-breathing so the reading isn’t affected.
   • Have him close his lips around the thermometer under the tongue toward the back (sublingual pocket), keep mouth closed and breathe through the nose while it registers.
   • Hold in place until the thermometer beeps; typical accuracy is ±0.2–0.4°F.

2. Rectal (most accurate core temperature)

   • Gives the most reliable reading, similar to core temperature; commonly used for infants but appropriate if you need accuracy.
   • Use a digital rectal thermometer, apply a water‑based lubricant, insert gently about 1–1.5 inches (2–4 cm) into the rectum, hold until it beeps. This will typically read ~0.5–1.0°F higher than oral.
   • It’s more invasive and some teens will refuse; it’s optional only if he and you are comfortable.

3. Axillary (underarm) — what you tried

   • It’s less accurate and often reads lower than core temp by ~0.5–1.0°F, so a “normal” axillary reading does not rule out fever.

Notes on thresholds and conversions

• Many schools use 100.4°F (38.0°C) as the fever cutoff for oral/tympanic. Rectal temps run higher (so expect ~0.5–1.0°F more).
• If you get an oral reading close to the cutoff (e.g., 100.2–100.6°F) and the school is strict, consider documenting with the thermometer and, if needed, follow school policy (stay home until fever-free per their guidance).

If you don’t own an oral or rectal digital thermometer:

• Buy a reliable digital oral/rectal thermometer (inexpensive, widely available). Forehead/ear thermometers are convenient but you said you don’t trust them.
• Pharmacy staff can advise; many stores sell same-day.

When to seek care

• If fever is high (≥104°F/40°C), persistent, your son is lethargic, severely dehydrated, has trouble breathing, severe headache, neck stiffness, rash, or other worrisome symptoms — seek urgent medical care or call your clinician.

This is general guidance. If you’re unsure or worried about his condition, contact your pediatrician for advice specific to your son.