Which specimen collection condition is most important when measuring cortisol?
1The specimen must be collected while the patient is fasting overnight
2The specimen must be protected from light during transport
3The time of collection must be recorded because of diurnal variation✓ 정답
4The specimen must be collected in a sodium citrate tube
해설
Cortisol concentrations vary widely with the time of day, so a result cannot be interpreted unless the time of collection is recorded. Fasting and protection from light are collection requirements for other analytes.