Dermal punctures are appropriate to use in all of the following patient scenarios except

Dermal punctures are appropriate to use in all of the following patient scenarios except

• A. Severe edema
• B. Obesity
• C. Neonatal patients
• D. Dehydration

Answer: (D)

Dermal puncture works best when there is good blood flow to the skin so capillary blood reflects the body's circulating levels. If peripheral perfusion is poor, the sample may be too small or not representative, leading to inaccurate results. In dehydration, the body compensates by constricting blood vessels in the extremities, which reduces skin blood flow. That makes a fingerstick or heel stick difficult to obtain and increases the likelihood of an unreliable sample, so dermal puncture is not appropriate in dehydrated patients. Other scenarios can still allow successful dermal puncture with appropriate technique: newborns routinely use this method because they require small-volume samples and venous access is often challenging; while severe edema or obesity can complicate the procedure, dermal puncture is not categorically ruled out in those cases and may be used with care, depending on the test requirements and sample integrity needed.

Dermal puncture works best when there is good blood flow to the skin so capillary blood reflects the body's circulating levels. If peripheral perfusion is poor, the sample may be too small or not representative, leading to inaccurate results.

In dehydration, the body compensates by constricting blood vessels in the extremities, which reduces skin blood flow. That makes a fingerstick or heel stick difficult to obtain and increases the likelihood of an unreliable sample, so dermal puncture is not appropriate in dehydrated patients.

Other scenarios can still allow successful dermal puncture with appropriate technique: newborns routinely use this method because they require small-volume samples and venous access is often challenging; while severe edema or obesity can complicate the procedure, dermal puncture is not categorically ruled out in those cases and may be used with care, depending on the test requirements and sample integrity needed.