When calculating total blood volume for a full-term, 2-day-old infant, which of the following information should a phlebotomist consider?

Choice A Reason:
Body temperature does not significantly affect serum cortisol levels and is not a factor that needs to be considered when planning to collect a cortisol specimen. Cortisol levels are regulated by the hypothalamic-pituitary-adrenal axis and not by body temperature.

Choice B Reason:
Time of day is a critical factor to consider when collecting a specimen for serum cortisol level measurement. Cortisol levels follow a diurnal pattern, peaking in the early morning hours and declining throughout the day, with the lowest levels typically occurring around midnight¹². This variation is known as the cortisol awakening response (CAR) and is important for accurately interpreting the results of the test.

Choice C Reason:
Alcohol consumption can affect cortisol levels; however, it is not typically a factor that a phlebotomist needs to consider immediately before specimen collection unless the patient is under the influence at the time of the test. Chronic alcohol use can lead to alterations in cortisol levels, but this is more of a consideration for the healthcare provider interpreting the results rather than the phlebotomist collecting the specimen.

Choice D Reason:
Prandial status, or the fed or fasting state of the patient, can influence cortisol levels, but it is not as significant a factor as the time of day. Cortisol levels can be slightly higher after eating, but this effect is generally considered minimal. The primary concern for prandial status would be if the cortisol test is being conducted alongside other tests that require fasting.

Choice A reason:
Turning the patient's hand palm down is not typically recommended as it can make the veins less accessible and may cause discomfort to the patient. The veins on the back of the hand are more superficial and can be more easily accessed when the hand is palm up.

Choice B reason:
Placing the patient in a supine position is not necessary for all venipuncture procedures and is usually reserved for patients who have a history of fainting or for those who are already lying down due to their medical condition. It is not a position that specifically increases comfort during the procedure.

Choice C reason:
Bending the patient's arm at the elbow can actually hinder the blood draw process as it may cause the veins to be less prominent and can lead to discomfort or movement during the venipuncture, potentially causing injury or an unsuccessful draw.

Choice D reason:
Positioning the patient's hand at waist level is the correct choice as it allows the arm to be in a natural, relaxed position, which can help the veins to be more prominent and accessible. It also helps in reducing the patient's anxiety as the arm is not in an awkward or strained position.