Capillary collection in infants is commonly used for which purpose, and why?

Capillary collection in infants is commonly used for which purpose, and why?

• A. Point-of-care glucose testing and newborn screening, with recognition that not all tests are valid with capillary blood
• B. Large-volume chemistry tests because infants have high blood volume
• C. Post-collection glucose testing requiring plasma
• D. Blood cultures because capillary blood is sterile

Answer: (D)

Capillary blood from a heel stick in infants is used because newborns have very limited total blood volume, so tests that need only a small amount of blood are ideal. The most common uses are newborn screening, which relies on dried blood spots collected from capillary blood, and rapid bedside tests like point-of-care glucose, where a tiny sample yields quick results. Tests not validated for capillary samples may be affected by factors such as hematocrit differences or sample contamination, so labs validate capillary-use for each test. Large-volume chemistry tests require more blood than capillary collection provides, and blood cultures are typically drawn venipuncture to obtain an adequate, sterile sample.

Capillary blood from a heel stick in infants is used because newborns have very limited total blood volume, so tests that need only a small amount of blood are ideal. The most common uses are newborn screening, which relies on dried blood spots collected from capillary blood, and rapid bedside tests like point-of-care glucose, where a tiny sample yields quick results. Tests not validated for capillary samples may be affected by factors such as hematocrit differences or sample contamination, so labs validate capillary-use for each test. Large-volume chemistry tests require more blood than capillary collection provides, and blood cultures are typically drawn venipuncture to obtain an adequate, sterile sample.