Temperature: Oral, Axillary, and Tympanic Routes

Why Temperature Comes First in the TPR Order

Vital signs are documented in TPR order - Temperature, Pulse, Respiration - and temperature is measured first because it directly affects the other values. A fever raises pulse and respiration; hypothermia depresses them. If the nurse sees an elevated pulse but no temperature reading, the picture is incomplete. In an Indiana long-term care facility, the CNA is the staff member who gathers all four baseline vital signs (temperature, pulse, respiration, and blood pressure) and reports them to the licensed nurse, who interprets them together.

Normal Ranges by Route

The body maintains a core temperature near 98.6 degrees F, but the number you read depends entirely on where you measure. Each route has its own normal range because skin and mucous membrane surfaces run cooler than the body core.

The one-degree difference between oral and axillary is the single most tested temperature fact on the Indiana CNA written exam. If you read 97.2 degrees F axillary, that is within the axillary normal range even though it would be below normal if read orally. Route notation prevents the nurse from misinterpreting a normal axillary reading as hypothermia.

The 15-Minute Post-Meal, Smoking, and Gum Rule

Oral temperature measures the temperature inside the oral cavity, not the body core. Anything the resident has had in the mouth recently changes that cavity temperature. Hot coffee raises it. Cold water lowers it. Smoking raises it because the warm smoke is inhaled and held in the mouth. Chewing gum increases salivation and can slightly lower or raise the reading depending on the gum temperature. The standard wait time is 15 minutes after the resident eats, drinks anything, smokes, chews gum, or brushes teeth before taking an oral temperature.

If you cannot wait 15 minutes, switch to the axillary or tympanic route and document why. A reading taken too soon is not just slightly off - a resident who just drank hot tea can register an oral temperature of 101 degrees F, which would trigger an unnecessary fever workup if the nurse does not know the timing. Always tell the nurse if you shortened the wait and used an alternate route.

Technique for Each Route

Oral Electronic Thermometer

1. Wash hands, don gloves.
2. Apply a disposable probe cover to the oral probe (blue-tipped probe in most facilities).
3. Ask the resident to open the mouth. Place the probe tip under the tongue, in the posterior sublingual pocket, to either the right or left of the frenulum.
4. Ask the resident to close the lips around the probe and breathe through the nose.
5. Hold the probe in place (or let the electronic unit beep) until the reading stabilizes.
6. Read the display, remove the probe, eject the cover into the waste receptacle.
7. Wipe the probe with facility-approved disinfectant if required by policy.
8. Remove gloves, wash hands, document with route notation.

Common error: Placing the probe tip in the front of the mouth or on top of the tongue. The posterior sublingual pocket is the most vascular area and gives the most accurate reading. The front of the mouth runs cooler.

Axillary Electronic Thermometer

1. Wash hands, don gloves.
2. Apply probe cover (green-tipped axillary probe in most facilities).
3. Pat the axilla dry with a towel if the resident is diaphoretic - moisture lowers the reading.
4. Place the probe tip in the center of the armpit.
5. Lower the resident's arm across the chest to hold the probe snug against the skin.
6. Wait for the electronic beep or hold per facility policy (often longer than oral - some units require a full 3-5 minutes on axillary mode).
7. Read, remove, eject cover, document with "ax" notation.

Common error: Not holding the arm down against the probe. If the arm is loose, air circulates in the armpit and the reading drops.

Tympanic Thermometer

1. Wash hands, don gloves (a clean probe cover is applied to the tympanic probe).
2. Attach a new disposable probe cover - never reuse a cover between residents.
3. Straighten the ear canal: for an adult, pull the pinna up and back; for a child under 3, pull down and back (you will not use this on infants in a LTC setting, but the principle matters).
4. Insert the probe gently into the ear canal opening and seal it.
5. Press the scan button. The unit beeps in 1-2 seconds.
6. Remove, eject the cover, document.

Common error: Not sealing the ear canal. If ambient air leaks in, the reading reflects room temperature, not body temperature.

Documentation With Route Notation

Every temperature reading must include the route. The Indiana CNA skills evaluation checks whether you document correctly, and the written exam tests it. The standard notations are:

• Oral: 98.6 T (oral) or 98.6 T-O
• Axillary: 97.2 T (ax) or 97.2 T-Ax
• Tympanic: 98.4 T (tympanic) or 98.4 T-Ty

Never record a number without the route. A temperature of 97.2 with no route could be a normal axillary reading or a dangerously low oral reading. The nurse cannot interpret it without the route, and the chart is a legal document - incomplete documentation is treated as no documentation in an Indiana survey or investigation.

When to Report

Report immediately to the licensed nurse if:

• Oral temperature is above 99.6 degrees F or below 97.6 degrees F (outside oral normal range).
• Axillary temperature is above 98.6 degrees F or below 96.6 degrees F (outside axillary normal range).
• The resident is diaphoretic, shivering, flushed, or complains of chills.
• The reading is outside the range the care plan flags for that resident (some residents have chronic low-grade temperatures; the care plan sets the report threshold).

Do not wait to finish the rest of the vital signs if the temperature is abnormal. Report it before moving to pulse.

Indiana Scope: Why Rectal Temperature Is NOT a CNA Task

The Indiana Administrative Code 410 IAC 16.2, Standard 14, lists the tasks a CNA may not perform. Rectal temperature measurement is classified as an invasive procedure. The rectal mucosa is a mucous membrane, and inserting a thermometer into it carries risk of perforation in a frail or confused resident. Only a licensed nurse performs rectal temperatures in an Indiana LTC facility. If a resident's oral and axillary routes are both unavailable (mouth surgery, bilateral axillary skin breakdown), the CNA notifies the nurse - the nurse decides on the route, not the CNA.

This scope rule is tested directly. A common distractor on the written exam describes a scenario where the oral and axillary routes are contraindicated and asks what the CNA should do next. The answer is always the same: notify the licensed nurse. Do not switch to rectal, do not guess, and do not delay.

Thermometer Safety and Infection Control

Every thermometer probe gets a disposable cover. The cover is applied before the probe touches the resident and ejected into the waste receptacle immediately after the reading. The probe itself is wiped with a facility-approved disinfectant between residents if your facility uses shared electronic units. Many Indiana facilities now assign each resident a dedicated thermometer or probe, stored in the room - check facility policy.

Gloves are worn for every temperature measurement because the probe touches mucous membranes (oral) or skin that may have micro-tears (axillary). Hand hygiene before and after is non-negotiable. The tympanic probe cover prevents earwax and skin flora from contaminating the unit, but the cover does not replace gloves - you still touch the resident's ear and pinna.

The Resident Who Cannot Hold the Oral Probe

If the resident is confused, unconscious, unable to follow instructions, or has facial weakness (such as after a stroke), the oral route is unsafe - the probe can be bitten, swallowed, or displaced. Switch to axillary or tympanic and document the reason. If you are unsure which route is appropriate for a resident with a specific condition, ask the nurse before you start. The skills evaluation penalizes candidates who choose oral for a resident whose chart says NPO (nothing by mouth) or who has recent oral surgery, even if the candidate's technique is otherwise correct.

Temperature and the Care Plan

Some residents have baseline temperatures outside the textbook normal range due to chronic conditions. An older resident may run 96.5 degrees F orally as a baseline. The care plan documents the resident's normal and sets the report threshold - for example, "report oral temp above 99.0 for this resident." Read the care plan before measuring if you are new to the resident. If no adjusted threshold is documented, use the standard normal range and report anything outside it.