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|Performed by||Los Angeles Children's Hospital|
|Collection Instructions||Specimens for this assay should be obtained when PKU is first suspected and before dietary restrictions are instituted.
Do NOT collect urine within 24 hours of a patient having been given a contrast agent for a radiologic study; contrast agents yield unreliable analytical results.
Shield samples from light during and after collection by wrapping the collection container in aluminum foil. Place aluminum foil over the collection bag for bagged patients. Promptly place urine specimens on ice after collection.
Filter paper circles should be completely filled with blood, soaking through from one side to the other. DO NOTE TOUCH ANY OF THE FILTER PAPER CIRCLES BEFORE OR AFTER COLLECTION. Dry the blood spots at room temperature for 2-4 hours while the paper is in a horizontal position. Cover the blood spots with the end flap of the collection device only after the specimen is completely dry.
|Container type||Urine cup without preservatives (on ice)|
|Amount to Collect||10 mL blood|
|Sample type||Random urine AND blood spots|
|Preferred volume||10 mL urine AND 4 completely filled blood spots on filter paper|
|Min. Volume||5 mL urine AND 4 completely filled blood spots on filter paper|
|UCSF Rejection Criteria||Samples not refrigerated or protected from light during collection and transport.|
|Processing notes||In DIM LIGHT, aliquot 10 mL of urine into a polypropylene tube. Wrap the tube in Aluminum foil to protect it from light and immediately freeze the tube at -20C.
Seal the dried blood spots in a plastic bag or tube and refrigerate them at 4C.
Complete all items on the special laboratory request form, order a "Pteridine Profile", and include the names, addresses, telephone numbers and fax numbers of anyone who should be notified of the results. Label the shipping container in large print "FREEZE PROMPTLY WHEN RECEIVED".
Ship the foil-covered urine container and the sealed container holding the dried blood spots together on dry ice.
To avoid weekend delivery, ship by overnight Federal Express on Monday-Wednesday only to: Children's Hospital Los Angeles, Department of Pathology and Laboratory Medicine, Special Chemistry Laboratory, Duque Bldg., 2nd Floor, Attn.: Won G. Ng, Ph.D, 4650 Sunset Blvd., Los Angeles, CA 90027, ph: (323) 669-2590, Fax: (323) 668-1047
|Normal range|| Normals:
From: Nederwieser A et al. 1980. Acta Helv Paediat. 25;335 and Blau, N. 1988. Ann REv Nutr. 8;185
|Synonyms||Biopterin; Neopterin; Dihyropteridine Reductase; DHPR; hyperphenylalaninemia; PKU|
|Turn around times||Test performed Monday-Friday. Turnaround time: 3-4 days|
|Additional information||The profile includes Biopterin, Neopterin, %Biopterin and Dihyropteridine Reductase (DHPR) levels. Biopterin metabolites are assayed to determine whether hyperphenylalaninemia is due to classical PKU or faulty biopterin metabolism.
Transfusions can falsely raise the level of dihyropteridine reductase (DHPR) activity for up to 90 days.
Reduced pteridines are unstable to light and heat; the urine collection must be protected from both during and after collection.
Handling and shipping charges are charged to the Neonatal Screening Program budget number for all specimens submitted as part of a recall followup of that program. Specimens not submitted as a recall followup must be billed to the patient or insurance
|CPT coding||82491-90, 82657-90|
|Last Updated||12/19/2012 4:32:41 PM|
If you have additional questions regarding this test, please call: 415-353-1667