What collection method is typically avoided for severely obese patients?

Capillary puncture is typically avoided for severely obese patients due to the difficulties associated with successfully obtaining a sample from an adequate site on the body. In individuals with significant obesity, the thickness of subcutaneous fat can make it challenging to locate appropriate capillary sites, such as on the fingers or heels, for effective puncture. Additionally, the volume of blood that can be obtained from capillary punctures is limited, which may not meet the needs for testing in patients who might require larger blood samples or in cases where higher accuracy and sensitivity of results are necessary.

In contrast, venipuncture, heel puncture, and finger puncture are often feasible for obese patients. Venipuncture typically uses larger veins and can provide a more substantial volume of blood, making it suitable for various tests. Heel punctures are mainly used for infants, not adults, so their relevance decreases in adults with obesity. Finger punctures could also be used, but the effectiveness and appropriateness of the site may often be compromised in severely obese individuals due to similar accessibility issues encountered in capillary punctures.