Final answer:
The blade depth on an infant lancet should be set according to the latest medical standards and individual infant characteristics, with recent guidance suggesting as much as 15 diameters deep, contrary to the older 7-8 diameters deep rule of thumb.
Step-by-step explanation:
The blade depth on an infant lancet should be carefully chosen to ensure that the blood sample can be collected safely and effectively. An older "rule of thumb" suggested a depth of 7-8 diameters deep, though more recent research advises as much as 15 diameters deep. It is vital to adjust the lancet appropriately according to the latest medical standards and individual infant characteristics such as gestational age and skin thickness.
Using an appropriate blade depth minimizes discomfort and potential complications for the infant. Since adequate penetration is necessary to obtain a blood sample while ensuring minimal trauma to the infant's skin, healthcare professionals must use their judgment and follow established guidelines for lancet selection and use.