Test Code Billings Clinic: 7678 Phenylketonuria (PKU) 2
Performing Laboratory
Montana Public Health Laboratory, Helena, Montana
Specimen Requirements
Specimen must arrive within 24 hours of collection.
Obtain specimen using a Newborn Screening Specimen Card (minimum volume: 5 completely filled circles) as follows:
- Sterilize, allow skin to dry, and puncture heel with sterile lancet.
- Allow large blood droplet to form.
- Touch filter paper to blood and allow to soak through completely in each circle. Total saturation of circles must be evident when paper is viewed on both sides. Do not apply blood to both sides.
- Use of capillary tubes is not recommended because they tend to roughen filter paper and cause over absorption.
- Allow blood spots to air dry thoroughly for 2 to 3 hours at ambient temperature. Keep away from direct sunlight and heat. Do not stack filter papers before they are thoroughly dried. A protective cover may be used to hold specimen while drying.
- Cover with end flap only after specimen is completely dry.
- Maintain sterility and forward promptly.
Reject Due To
- All circles are not completely filled
- Blood is layered by application on both sides or by multiple spotting
- Filter paper is scuffed or torn
- Specimen is contaminated or improperly dried
- Incomplete information
Reference Values
Reference values are included with patient’s report.
Test Classification and CPT Coding
82775 - galactose
83516 - cystic fibrosis
84030 - phenylalanine
84437 - thyroxine T4
84443 - thyroid-stimulating hormone (TSH) (if appropriate)
Profile/Testing Information
Includes cystic fibrosis, galactose, phenylalanine, and thyroxine (T4).
Reflex Information:
If T4 is <10 µg/dL; Billings Clinic: #4056 “Thyroid-Stimulating Hormone (TSH), Plasma” reflex testing will be performed at an additional charge.