A phlebotomist should verify that a patient has fasted for how long prior to obtaining a fasting specimen?

Choice A Reason:
The patient's condition is a critical factor as it can influence the ease of blood collection and the choice of collection site. For example, a dehydrated patient may have less accessible veins. Patient age is also important; pediatric and geriatric patients may require different approaches due to vein size and fragility. The blood volume required for testing must be considered to ensure sufficient sample size without compromising patient safety, adhering to guidelines that limit blood collection to a certain percentage of the patient's total blood volume.

Choice B Reason:
While patient height and gender may influence the choice of blood collection site, they are not as critical as the factors listed in choice A. Patient medications are important to consider, as some medications may affect coagulation or the integrity of the sample.

Choice C Reason:
The ordering physician's preferences may be considered, but they are not a primary factor in the method of collection. The number of tests ordered and the diagnosis can influence the volume of blood needed but are secondary to the patient's condition and safety considerations.

Choice D Reason:
The time of day and the timing of the specimen collection can be important for certain tests that are time-sensitive or influenced by diurnal variations. The test status, whether routine or stat, may affect the urgency of collection but not necessarily the method of collection.

Choice A reason:
The BUN test measures the amount of urea nitrogen in the blood, which can indicate kidney function. Fasting is not typically required for a BUN test unless it is being conducted alongside other tests that may require fasting.

Choice B reason:
An HDL test is part of a lipid profile that measures the levels of good cholesterol in the blood. Fasting before a cholesterol test, including HDL, is often recommended to ensure accuracy, although recent guidelines have changed, allowing for nonfasting cholesterol testing in certain individuals.

Choice C reason:
An ABG test measures oxygen and carbon dioxide levels in the blood and assesses the body's acid-base balance. Preparation for an ABG test does not typically require fasting, but patients may need to stop supplemental oxygen before the test to get accurate measurements.

Choice D reason:
A CBC test, or complete blood count, does not require fasting. It measures various factors of the blood, including red and white blood cells and platelets. Fasting is not necessary unless the CBC is part of a panel of tests that includes tests requiring fasting.