A phlebotomist has collected a lactic acid sample and needs to prepare the sample for processing and transportation. Which of the following methods is correct?

Choice A reason:
When performing a capillary blood collection, such as a fingerstick, the lancet should be positioned perpendicular to the fingerprint grooves. This orientation helps to ensure that the incision is made across the ridges of the fingerprint, which can facilitate a better blood flow and make it easier to collect an adequate sample without needing to squeeze the finger excessively, which could hemolyze the sample.

Choice B reason:
Positioning the lancet parallel to the nail bed is not recommended because it can result in a cut that runs along the length of the fingerprint grooves, which may not bleed as freely and could also be more painful for the patient.

Choice C reason:
Using the lancet along the lateral portion of the first digit is not part of the standard aseptic technique protocol for capillary blood collection. The first digit, or thumb, has a pulse and should generally be avoided because it can be more sensitive and is more prone to bruising.

Choice D reason:
The medial portion of the fifth digit, or the little finger, is also not a recommended site for capillary blood collection with a lancet. The little finger is typically smaller and may not provide an adequate site for blood collection, and similar to the thumb, it can be more sensitive and prone to injury.

Choice A Reason:
An angle of 50° is too steep for venipuncture and increases the risk of going through the vein and causing injury to structures beneath it. A steeper angle can also make it more difficult to control the depth of the needle, leading to an increased chance of puncturing the posterior wall of the vein.

Choice B Reason:
An angle of 30° is the recommended angle for venipuncture as it allows for a smooth entry into the vein without going too deep. This angle helps to ensure that the needle enters the vein in a controlled manner and minimizes the risk of injury to the patient. It also provides a good balance between ease of entry and control over the needle's depth.

Choice C Reason:
An angle of 90° is not recommended for venipuncture because it is perpendicular to the skin, which greatly increases the risk of passing through the vein entirely and causing injury. This angle does not allow for any control over the depth of the needle and is likely to cause discomfort or pain to the patient.

Choice D Reason:
An angle of 75° is also too steep for safe venipuncture. Similar to a 50° angle, it increases the risk of penetrating the posterior wall of the vein and potentially damaging surrounding tissues or arteries. It is important to use a lower angle to ensure the safety and comfort of the patient during the procedure.