Interpreting a Mixed-Unit Temperature Log
A student nurse records a patient's oral temperature four times in one shift. The readings are 98.6 °F at 08:00, 37.8 °C at 12:00, 100.4 °F at 16:00, and 38.9 °C at 20:00. The patient's chart lists a baseline oral temperature of 37.0 °C, and the unit's protocol flags a fever when the temperature exceeds 38.0 °C. The student also notes that the 16:00 reading was taken 10 minutes after the patient drank a cup of hot tea, while the other readings were taken at least 30 minutes after any food or drink.
1. Convert all four readings to a single scale and identify which readings cross the fever threshold.
Read the worked answer
Use °C = (°F − 32) × 5/9.
- 98.6 °F → (98.6 − 32) × 5/9 = 66.6 × 5/9 = 37.0 °C
- 37.8 °C → 37.8 °C
- 100.4 °F → (100.4 − 32) × 5/9 = 68.4 × 5/9 = 38.0 °C
- 38.9 °C → 38.9 °C
Threshold is greater than 38.0 °C. So 38.0 °C does not cross it (it equals it), while 38.9 °C does. Only the 20:00 reading is a protocol-defined fever.
2. The student wants to report the 16:00 reading as a fever. Using the timing detail, argue for or against that interpretation.
Read the worked answer
Argue against treating 16:00 as a true fever. The reading equals the threshold exactly (38.0 °C), so it does not exceed it, and it was taken only 10 minutes after hot tea - a known confounder for oral temperature. The protocol-compliant readings (08:00, 12:00, 20:00) were all taken ≥30 minutes after food or drink. The defensible conclusion: the only unambiguous fever is 20:00 at 38.9 °C; the 16:00 value should be rechecked, not charted as a fever.
3. The patient's baseline is 37.0 °C. By how many Celsius degrees does the 20:00 reading exceed baseline, and what is that change in Fahrenheit degrees?
Read the worked answer
Celsius change: 38.9 − 37.0 = 1.9 °C.
A Celsius interval converts by ×9/5 (no +32 offset, because offsets cancel for differences): 1.9 × 9/5 = 3.42 °F.
Check: 37.0 °C = 98.6 °F; 38.9 °C = 101.02 °F (38.9 × 9/5 + 32 = 70.02 + 32). 101.02 − 98.6 = 3.42 °F. ✓