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HelpTest Code LAB3521 Tripeptidyl Peptidase I
Clinical System Name
Tripeptidyl Peptidase I
Synonyms
NCL
TPP
Neuronal ceroid lipofuscinoses
CLN2
TPP I
Sample Requirements
Specimen: Whole Blood
Container(s): Yellow/ACD A or B, Dark Green/Sodium Heparin Tube
Preferred Vol:10.0 mL
Minimum Vol: 6.0 mL
Note: Sample must be processed within 24 hours.
Also acceptable: Dried blood spots; 2 full circles on a newborn screening card or cultured cells from skin fibroblasts (2 confluent T-25 flasks).
Processing Instructions
Reject due to:
Spin: N
Aliquot:N
Temp:RT
Storage location: Biochemical Genetics Box- RT
Weekend Processing: Contact Chem West (x72565) on dayshift. If Chemistry team is unavailable, sample should be stored in RT Biochemical Genetics box.
Off-site collection: Do not spin! Keep at room temperature. Transport Mon-Thurs at room temperature via overnight shipping.
Stability
| Specimen Type | Temperature | Time |
|---|---|---|
| whole blood | RT |
24 h |
| whole blood | 2-8 C | 24 h |
Contact Biochemical Genetics Laboratory for specimens received outside of stability.
Availability
| STAT | Performed | TAT |
|---|---|---|
| N | Weekly | 7-10 days |
Contact the Biochemical Genetics Lab for requests outside of stated availability (206)987-2216.
Performing Laboratory
Seattle Children's Laboratory
Department
Department: Biochemical Genetics
Phone Number: 206-987-2216
CPT Codes
82657
Methodology
Method: Fluorometric Enzyme assay
Analytical Volume:
Limitations:
Reference Range
| Specimen Type | Normal Range |
|
WBC |
70-300 nmol/hr/mg protein |
| Blood Spots | 30-220 nmol/hr/spot |
Description
Fluorometric enzyme assay for tripeptidyl peptidase
Clinical Utility
About 80% of patients with late infantile NCL and 7% of pateints with juvenile onset NCL have a deficiency of the lysosomal enzyme tripeptidyl peptidase 1 (TPP1). Disease is characterized by seizures, ataxia, myoclonus, psychomotor retardation, vision loss and speech impairment.
Special Instructions
Links to:
Consent Forms
Algorithms
Requisition
Biochemical Genetics Requisition
On the requisition include clinical information needed for appropriate interpretation. (Age, gender, drug therapy and family history)