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Test ID TPPTL Tripeptidyl Peptidase 1 and Palmitoyl-Protein Thioesterase 1, Leukocytes

Useful For

Evaluation of patients with clinical presentations suggestive of neuronal ceroid lipofuscinoses (NCL)


Aids in the differential diagnosis of infantile and late infantile NCL


This test is not useful for detecting carrier status of NCL.

Genetics Test Information

This blood test is an appropriate first step for individuals who present between 0 and 4 years of age with symptoms consistent with neuronal ceroid lipofuscinosis.

Method Name


Reporting Name

TPP1 and PPT1, WBC

Specimen Type

Whole Blood ACD

Shipping Instructions

For optimal isolation of leukocytes, it is recommended the specimen arrive refrigerated within 6 days of collection to be stabilized. Collect specimen Monday through Thursday only and not the day before a holiday. Specimen should be collected and packaged as close to shipping time as possible.

Specimen Required


Preferred: Yellow top (ACD solution B)

Acceptable: Yellow top (ACD solution A)

Specimen Volume: 6 mL

Collection Instructions: Send specimen in original tube. Do not aliquot.

Specimen Minimum Volume

5 mL

Specimen Stability Information

Specimen Type Temperature Time Special Container
Whole Blood ACD Refrigerated (preferred) 6 days YELLOW TOP/ACD
  Ambient  6 days YELLOW TOP/ACD

Reference Values


85-326 nmol/hour/mg protein



20-93 nmol/hour/mg protein

Day(s) Performed

Preanalytical processing occurs Monday through Saturday.

Assay performed: Twice per month

Performing Laboratory

Mayo Clinic Laboratories in Rochester

CPT Code Information


LOINC Code Information

Test ID Test Order Name Order LOINC Value
TPPTL TPP1 and PPT1, WBC 93704-5


Result ID Test Result Name Result LOINC Value
50688 Specimen 31208-2
50689 Specimen ID 57723-9
50690 Source 31208-2
50691 Order Date 82785-7
50692 Reason for Referral 42349-1
50693 Method 85069-3
50694 TPP1L 76038-9
50695 PPT1L 74935-8
50696 Interpretation 59462-2
50697 Amendment 48767-8
50698 Reviewed By 18771-6
50699 Release Date 82772-5

Test Classification

This test was developed and its performance characteristics determined by Mayo Clinic in a manner consistent with CLIA requirements. This test has not been cleared or approved by the U.S. Food and Drug Administration.

Report Available

8 to 15 days

NY State Approved



1. New York Clients-Informed consent is required. Document on the request form or electronic order that a copy is on file. The following documents are available in Special Instructions:

-Informed Consent for Genetic Testing (T576)

-Informed Consent for Genetic Testing-Spanish (T826)

2. Biochemical Genetics Patient Information (T602) in Special Instructions

3. If not ordering electronically, complete, print, and send an Inborn Errors of Metabolism Test Request (T798) with the specimen.