CNA Practice Test
Vital signs and reportingQuestion 507 of 1700

How far do you insert a rectal thermometer in an adult?

  1. 5 to 6 cm, with an oil-based lubricant on the cover
  2. 10 cm, with no lubricant on the probe cover
  3. 2 to 3 cm or less, with a water-based lubricant
  4. 6 to 8 cm, dry cover, with a firm push
Show answer

Correct answer: 2 to 3 cm or less, with a water-based lubricant

Insert gently 2-3 cm or less, depending on size.

Source: Nursing Assistant (Reuter), 7.8: Skills Checklist- Oral Tympanic Axillary Rectal and Temporal Temperatures

Practice vital signs and reporting

Questions last reviewed: 18 October 2026