Kapillærpunktion

Kapillærpunktion, also known as finger‑stick or heel‑stick, is a minimally invasive technique for obtaining a small volume of blood from capillary beds, typically in the fingertip of an adult or the heel of an infant. The practitioner cleans the puncture site with an antiseptic, then presses a lancet or needle through the skin to create a capillary wound. The resulting blood is collected either in a microcollection tube or on a filter paper spot for transport.

This method is widely used in point‑of‑care testing, pre‑operative screening, and for home blood glucose monitoring. It is preferred when venous access is difficult, when rapid results are needed, or when only small sample volumes are required for assays such as hemoglobin, electrolyte panels, or blood gases. Capillary sampling is also common for newborn metabolic screening, where dried blood spots are collected on filter paper for later laboratory analysis.

Advantages of kapillærpunktion include ease of performance, reduced pain compared to venipuncture, lower risk of blood loss, and minimal equipment requirements. However, capillary blood can be affected by local tissue contamination, misleadingly high glucose levels after intense exercise, and a lower accuracy for certain measurements such as hematocrit or oxygen saturation compared with venous blood. Proper technique—adequate cleaning, correct lancet depth, and gentle finger or heel squeezing—helps to mitigate these issues.

In clinical practice, kapillærpunktion remains a staple of bedside diagnostics, particularly in settings where rapid, low‑volume sampling is essential, such as emergency care, field medicine, and home health monitoring.