Heel Sticks

Heel Sticks

 

I’m sure you do not remember when you had your heel stick—a tiny blade poked into your heel minutes after you were born. Given the trauma of what you had just been through, leaving the comfort of your mother’s 98.6° F body into the cool 70° F room, breathing air for the first time, and squeezing out of a very small place, the heel stick was the least offensive part of your birth day. The wealth of information gained from this single heel stick is extraordinary, considering that all that is recovered from a heel stick is a few drops of blood.

 

 

The heel stick is a bit different from most other blood draws that you will have in your life. Instead of a needle puncturing a vein and withdrawing blood under vacuum into a tube, a heel stick requires only a tiny incision be made on the heel of the foot. Into the small opening that is made, a capillary tube is placed and blood is drawn into the tube by capillary action (hence the name). This small amount of blood is sent for a host of studies.

 

There are several common tests that are performed on the blood obtained in a heel stick. General chemistries may be tested such as sodium, potassium, and chloride levels along with kidney function. Liver function tests may be performed along with a bilirubin level which can be important to test in babies with the yellow skin of jaundice. Complete blood counts measure the red blood cells, white blood cells, and platelets, among other cell types in the blood. Sometimes if there is a particular concern, toxicology and blood gas analysis can be measured in the blood obtained from a heel stick. The baby’s glucose can be tested as well, which is sometimes important if the infant’s mother developed gestational diabetes (diabetes that appears during pregnancy).

 

The other (perhaps most important) test that is performed on the heel stick blood is the newborn screening. A newborn screening is actually a test for a large number of genetic or congenital diseases. The diseases that are screened in the newborn screening vary a bit from state to state but there are some that are almost always included. Some of the most common genetic disorders for which there is testing in a heel stick is phenylketonuria (PKU), galactosemia, sickle cell anemia, cystic fibrosis, maple syrup urinedisease, homocystinuria, congenital hypothyroidism, congenital adrenalhyperplasia, and tyrosinemia, among others. As the genetic basis for diseases are discovered, the number of diseases that are included on the newborn screening heel stick may increase.

 

In general, the infant never realizes that the heel stick has taken place. The area is sterilized ahead of time and the complication rate is extremely low. Even the parents may not even realize that the heel stick has taken place (other than giving consent for the procedure). Diagnosing one of the diseases included on the newborn screening heel stick can be life-saving and can provide the earliest possible detection.