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Paediatric Laboratory Medicine

Phenylalanine and Tyrosine, Blood Spot

Background

Phenylalanine and tyrosine are proteinogenic amino acids that when elevated are consistent with PKU related disorders and tyrosinemia (Type I, II and III). Monitoring of blood concentration is important for the effective management of these metabolic disorders. Dried blood spots provide an effective mechanism for sample transport allowing collections to occur outside of a clinical setting.

Test Name

Phenylalanine and Tyrosine, Blood Spot

Alternate Name/ Synonym

PKU, bloodspot

Test Code

YPHEB, YTYRB

Division

Metabolic Diseases

Turn Around Time

1 week

Specimen Type

Blood spot

Minimum Specimen Requirements

Saturated filter paper circle. Recommend 2 full circles on a Specimen Collection Card.

Storage/Transportation

Allow sample to completely air dry before shipping at room temperature

Shipping and Contact Information

The Hospital for Sick Children
Rapid Response Laboratory
170 Elizabeth Street, Room 3642
Toronto, ON
M5G 2G3
Canada
Phone: 416-813-7200
Phone: 1-855-381-3212

Reference Range

Reference Intervals Chart - Units = µmol/L
Reference ranges are age dependent.

Test

0 - 6d

7d- <1mo

1mo- <1y

1- <13y

13- <19y

>19y

Phenylalanine

49-107

49-107

52-116

55-100

55-100

40-85

Tyrosine

27-187

27-187

34-151

45-126

34-88

28-87