Dihydropteridine Reductase (DHPR) Deficiency

Abbrev Code:XMISC   
Order Code:LAB4909Order Name:Laboratory Miscellaneous Order
Synonyms:Pteridine; Biopterin
CPT Codes: 82657 x1
Turnaround Time:Specimens are sent to the reference laboratory Mon-Thur; results are reported within 7 business days.
Special Instructions:A completed requisition must accompany each specimen. See Associated Links.
Associated Links:

CHLA Biochemical Genetics Special Chemistry Requisition

Collection Instructions

Optimal Volume:0.5 mL to saturate 3-5 13mm circles on filter paper
Container:Filter paper
Collection Instructions:Apply blood from heelstick to (apply to one side only) filter paper until each circle is filled completely when viewed from the other side. Avoid repeated applications; allow circles to fill by natural flow. Do not use pipet or capillary device. Allow to air dry for three hours and transport to laboratory in an unsealed specimen transport bag. Do not expose to heat or moisture.
Causes for Rejection:Insufficient blood to fill in circles, improper storage at high temperature which causes denaturation of the enzyme in the blood spots.

Processing and Shipping

Specimen Processing:Mix whole blood and fill 3-5 circles on filter paper. Allow to dry completely. Store frozen.
Shipping Instructions:Ship frozen.
Test Performed at or Referral Lab Lab Sendouts  (Children's Hospital of Los Angeles)


Reference Range:1.96 - 7.51 units
Use:Dihydropteridine reductase deficiency accounts probably less than 5% of hyperphenylalaninemia,

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