Which of the following tests has a fasting requirement?

Choice A Reason:
The red top tube is typically used for serum determinations in chemistry, serology, and blood bank. It contains no additive or may contain a clot activator. The red top tube is not the first choice for capillary puncture order of draw because it is designed for tests that require serum and not whole blood.

Choice B Reason:
The lavender top tube is used for whole blood hematology determinations, as it contains EDTA as an anticoagulant. According to the order of draw for capillary punctures, the EDTA tube should be collected first to ensure adequate volume and accurate hematology test results. This makes the lavender top tube the correct choice for the first collection in this scenario.

Choice C Reason:
The light blue top tube contains sodium citrate and is used for coagulation tests. In venipuncture, it is drawn after the blood culture bottle and before other tubes to prevent contamination with additives from other tubes. However, for capillary punctures, it is not the first choice as hematology tests take precedence.

Choice D Reason:
The royal blue top tube is used for trace element, toxicology, and nutrient determinations². While it may be used for lead and toxicology screens mentioned in the question, it is not the first tube to be drawn in a capillary puncture sequence. The EDTA tube (lavender top) is drawn first to prevent clotting and ensure accurate CBC results.

Choice A reason:
The axillary vein is not commonly used for routine venipuncture due to its location in the armpit area, where it is more difficult to access and poses a higher risk of complications.

Choice B reason:
The median cubital vein is often the vein of choice for venipuncture due to its size and accessibility. However, in the case of a patient with bilateral scarring on the forearms, this vein may be compromised, making it a less suitable option.

Choice C reason:
The basilic vein, while also a common site for venipuncture, is located on the inner aspect of the arm and may be affected by the scarring on the patient's forearms. Additionally, it is closer to nerves and arteries, which increases the risk of complications.

Choice D reason:
The dorsal hand veins are a good alternative for venipuncture when the more common sites are not available, such as in the case of a patient with bilateral scarring on the forearms. These veins are usually more superficial and can be accessed with minimal risk of complications.