Temperature Measurement

Body temperature reflects the balance between heat production and heat loss. CNAs measure temperature using various methods and must understand normal values for each method.

Normal Temperature Ranges by Route

Remember:

• Rectal is about 1 degree HIGHER than oral
• Axillary is about 1 degree LOWER than oral

Types of Thermometers

Oral Temperature

When to Use:

• Alert, cooperative adults
• Patients who can hold thermometer under tongue
• No mouth injuries or recent oral intake

When NOT to Use:

• Unconscious patients
• Patients on oxygen by mask
• After eating, drinking, or smoking (wait 15-30 minutes)
• Patients who cannot close mouth
• Infants and young children

Procedure:

1. Apply disposable probe cover
2. Place under tongue, to one side
3. Ask patient to close lips around thermometer
4. Wait for beep or required time
5. Read and record temperature
6. Dispose of probe cover
7. Clean thermometer per facility policy

Rectal Temperature

The most accurate method, but most invasive.

When to Use:

• When oral route is not possible
• Infants (though less common now)
• Unconscious patients
• Baseline readings

When NOT to Use:

• Rectal surgery, injury, or disease
• Diarrhea
• Hemorrhoids
• Patients on blood thinners (risk of bleeding)
• Cardiac patients (stimulates vagus nerve)

Procedure:

1. Provide privacy, position patient on side
2. Put on gloves
3. Apply probe cover and lubricate tip
4. Expose only anal area
5. Separate buttocks, insert thermometer 1/2 to 1 inch
6. Hold in place (never leave unattended)
7. Wait for beep or required time
8. Remove, wipe, read and record
9. Clean thermometer and area

Axillary Temperature

The least accurate method, but least invasive.

When to Use:

• When other routes are contraindicated
• Some patient preferences
• Screening purposes

Procedure:

1. Expose armpit, ensure it is dry
2. Place thermometer in center of armpit
3. Hold arm close to body
4. Wait for beep or 8-10 minutes
5. Read and record (note route: "axillary")

Tympanic (Ear) Temperature

Measures infrared heat from the eardrum.

Procedure:

1. Apply disposable probe cover
2. Pull ear up and back (adults) or down and back (infants)
3. Insert probe gently into ear canal
4. Press button and wait for beep (1-2 seconds)
5. Read display and record

Factors Affecting Accuracy:

• Excessive earwax
• Ear infection
• Hearing aids (remove first)
• Lying on ear (wait 5 minutes after)

Temperature Abnormalities

Report These Immediately:

• Temperature above 101°F or below 97°F
• Sudden change from baseline
• Patient complaints of feeling hot or cold with abnormal reading