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|Performed by||Western Clinical Laboratory|
|Collection Instructions||Draw > 12 hours after birth or immediately prior to an earlier blood transfusion.
Do not use capillary tubes for collection of the blood spot specimen and do not collect from a site other than a heel stick: deviations from the standard collection method of direct spotting of heel stick blood onto the filter paper can give false-negative results.
It is advised to submit a sample of cord blood in a Lavender top tube (label it "NSP") to the blood bank for follow-up hemoblobinopathy testing if required.
|Container type||Filter paper|
|Preferred volume||5 completely filled blood spots
Recommend that one full EDTA (Lavender top) vacutainer of cord blood be submitted to be held by the blood bank should further testing be required.
|Processing notes||1. Complete the Specimen Transport Log
2. Place samples and the completed Specimen Transport Log into a GSO or large manilla envelope
3. Apply shipping label
- Monday - Thursday: Use label marked PDS
- Friday: Use label marked SDS
4. Peel off the GSO tracking label at tthe bottom of the shipping label and place on a copy of the Specimen Transport Log for our records. Specimens may be tracked at www.gso.com
5. Place envelope in M503 by 1630 hours for pickup
6. send copy of the Sepcimen Transport Log to CB send-outs "Attn: Maxi Cruz"
|Normal range|| Acylcarnitine profile:
|Synonyms||Cord blood; newborn screen; state screening; Guthrie spots|
|Turn around times||9-12 days|
|Additional information||Infants are screened for Galactosemia, sickling and some other Hemoglobinopathaies, primary Hypothyroidism and Phenylketonuria (PKU).
Galactose transferase results ≤ 40 enzyme units are considered a positive screen and a heparinized whole blood specimen should be submitted for followup (see entry for Galactose-1-Phosphate Uridyl Transferase (under Galactose-1-Phophate).
Phenylalanine/tyrosine ratio of ≥ 1.5 will require followup submission of a second specimen; if a tyrosine level cannot be performed, the cutoff requiring followup will be a phenylalanine level ≥ 200 µmol/L. A phenylalanine level ≥ 400 µmol/L is deemed positive regardless of the phe/tyr ratio.
The Newborn Screening Program is not screening for abnormalities of tyrosine metabolism, but results ≥ 700 µmol/L are very unusual and a repeat assay taken 5-7 days later after adding vitamin C to the diet and decreasing the protein intake is recommended; it will be performed without charge by the State Genetic Disease Testing Laboratory. Benign elevations of tyrosine occur frequently in premature infants with high protein intakes (> 5 g/kg of dietary intake) and/or inadequate vitamin C. Supplementation with 100-150 mg/d of vitamin C and reducing protein intake to 3 g/kg is recommended, and usually results in lower tyrosine levels within 2-3 weeks. In contrast, tyrosine elevations usually remain high in patients with metabolic disorders, and are commonly accompanied by the development of other symptoms.
Because the test for hemoglobinopathies is only valid in untransfused neonates a specimen of cord blood in a lavender top tube (label the specimen "NSP") should be routinely submitted to the Blood Bank, and will be retained for two weeks in case the usual filter paper specimen submitted to the screening program gives evidence of prior transfusion. The test results assume no transfusion prior to testing. The types of abnormal hemoglobins are reported in order of relative frequency, but not the percentage of each type. Clinically significant hemoglobinopathies currently identified by the Screening Program include sickle cell anemia, sickle hemoglobin C, sickle hemoglobin D, sickle hemoglobin E, sickle beta thalassemia, beta-0 thalassemia, most cases of Hemoglobin H disease (including Hb H-Constant Spring disease), and some cases of alpha-thalassemia disease and alpha-thalassemia trait.
An infant should have only one Neonatal Screen. If the test for PKU is to be repeated because, e.g., the Screen was performed soon after birth (possibly because of early discharge), do NOT submit a second Neonatal Screen or use the filter paper form-instead submit blood for Phenylalanine (see entry for Phenylalanine). The urine of patients newly found to have a high serum phenylalanine level should be tested for biopterin metabolites (see entry for Pteridine Profile), to ensure that the diagnosis of PKU is not confounded with tetrahydrobiopterin deficiency.
IF AN ABNORMALITY IS DETECTED There is no direct patient charge for a neonate recalled by the state Screening Program or for the parents; contact the Newborn Screening Area Service Center for the San Francisco region at Stanford University Medical Center (650) 812-0353 for instructions. If this patient is being followed at UCSF, contact the Genetics Counselor for the Biochemical Genetics Service, x69997. Beeper Monday-Friday 8-5 PM 719-6813 or the Genetics Fellow on-call evening/weekends 719-9075.
Starting July 11, 2005, the California Newborn Screening (NBS) Program is expanding the screening for classical congenital adrenal hyperplasia (CAH) and multiple additional metabolic disorders detectable via tandem mass spectrometry (including amino acids, organic acid and fatty acid oxidation disorders). Due to biological variability of newborns and differences in detection rates for the various disorders in the newborn period, the Newborn Screening Program will not identify all newborns with these conditions. While a positive screening result identifies newborns at an increased risk to justify a diagnostic work-up, a negative screening result does not rule out the possibility of a disorder. Health care providers should remain watchful for any sign or symptoms of these disorders in their patients. A newborn screening result should NOT be considered diagnostic, and cannot replace the individualized evaluation and the diagnosis of an infant by a well-trained, knowledgeable health care provider. If you have any questions regarding these results, please contact the Newborn Screening staff at Stanford University Medical Center, (650) 812-0353.
|Last Updated||3/25/2013 12:38:21 PM|