ASCP (American Society for Clinical Pathology) Phlebotomy Technician Certification Practice Exam

A fingerstick is not suitable for coagulation tests because these tests require accurate measurement of specific factors in the blood that can be influenced by the collection method. Venous blood draws are preferred for coagulation testing to ensure that the sample reflects true blood composition without the interference that could arise from capillary sampling. Capillary blood obtained through a fingerstick can be mixed with interstitial fluid and may not provide the precise results needed for coagulation studies.

In other scenarios presented, routine blood tests can be performed using a fingerstick when appropriate. Patients who are allergic to needles typically still require blood sampling, and fasting does not negate the ability to perform a fingerstick; however, it might be necessary to monitor specific blood glucose levels. Therefore, the correct choice emphasizes the limitation of fingerstick techniques in obtaining reliable samples for coagulation tests.