Heel Stick Blood Test
Overview
The heel stick blood test, also known as heel prick or capillary blood sampling, is a crucial screening procedure performed on newborns to detect various metabolic and hematologic conditions.
Key Points
- Most commonly performed between 24-48 hours after birth
- Part of mandatory newborn screening programs worldwide
- Can detect over 50 different metabolic and genetic disorders
- Requires minimal blood volume (0.5-1.0 mL)
- Results typically available within 24-72 hours
Step-by-Step Procedure
Pre-Procedure
- Verify patient identity and required tests
- Ensure proper warming of the heel (38°C for 3-5 minutes)
- Position infant securely with heel below heart level
- Identify correct puncture site using anatomical landmarks
Anatomical Considerations
Safe puncture areas include:
- Medial and lateral plantar surfaces of the heel
- Avoid posterior curvature and central area of heel
- Maximum puncture depth: 2.0mm for infants >2.5kg
- Maximum puncture depth: 1.4mm for infants <2.5kg
Technique
- Clean site with alcohol swab and allow to dry
- Hold heel firmly but gently
- Puncture perpendicular to skin surface
- Wipe away first drop of blood
- Collect subsequent drops on filter paper or collection device
- Apply gentle intermittent pressure
- Ensure complete filling of collection circles
Clinical Indications
Primary Screening
- Phenylketonuria (PKU)
- Congenital hypothyroidism
- Galactosemia
- Maple syrup urine disease
- Sickle cell disease
- Cystic fibrosis
- Congenital adrenal hyperplasia
Other Indications
- Blood glucose monitoring
- Bilirubin levels
- Hemoglobin assessment
- Blood gas analysis
Contraindications
- Local infection at puncture site
- Previous heel stick at same site within 24 hours
- Edema of the heel
- Poor peripheral perfusion
Required Equipment
- Sterile lancet (automated or manual)
- Filter paper collection cards
- Alcohol swabs
- Clean gloves
- Gauze pads
- Warming device (if needed)
- Band-Aid or adhesive tape
- Specimen labels
- Biohazard container
Equipment Specifications
- Lancet depth: 0.85mm to 2.0mm (age/weight dependent)
- Filter paper: Standardized Whatman 903 or equivalent
- Collection circles: 12-15mm diameter
Complications & Management
Common Complications
- Pain and discomfort
- Bruising
- Scarring
- Infection
- Inadequate sample collection
Prevention Strategies
- Proper site selection and technique
- Adequate warming before procedure
- Strict aseptic technique
- Proper pressure application
- Regular rotation of puncture sites
Quality Assurance
- Proper specimen handling
- Temperature control during transport
- Documentation requirements
- Storage conditions
