Sign in →

Test Code NEURF Neuraminidase, Fibroblasts

Reporting Name

Neuraminidase, Fibroblasts

Useful For

Aids in the diagnosis of sialidosis and galactosialidosis

Additional Tests

Test ID Reporting Name Available Separately Always Performed
FIBR Fibroblast Culture Yes Yes
CRYOB Cryopreserve for Biochem Studies No Yes

Testing Algorithm

When this test is ordered, a fibroblast culture and cryopreservation for biochemical studies will always be performed at an additional charge. However, for multiple lysosomal enzyme assays on a patient utilizing fibroblast culture, only 1 culture is required regardless of the number of enzyme assays ordered. If viable cells are not obtained within 10 days, client will be notified.

Method Name

NEURF: Fluorometric Enzyme Assay

CRYOB: Fibroblast Subculture Followed by Cryopreservation and Storage

Performing Laboratory

Mayo Medical Laboratories in Rochester

Specimen Type


Specimen Required

Submit only 1 of the following specimens:


Specimen Type: Cultured fibroblasts

Container/Tube: T-75 or T-25 flask

Specimen Volume: 1 Full T-75 flask or 2 full T-25 flasks

Specimen Stability Information: Ambient (preferred)/Refrigerated <24 hours


Specimen Type: Skin biopsy

Supplies: Fibroblast Biopsy Transport Media (T115)

Container/Tube: Sterile container with any standard cell culture media (eg, minimal essential media, RPMI 1640). The solution should be supplemented with 1% penicillin and streptomycin. Tubes can be supplied upon request (Eagle's minimum essential medium with 1% penicillin and streptomycin [T115]).

Specimen Volume: 4-mm punch

Specimen Stability Information: Refrigerated (preferred)/Ambient

Specimen Stability Information

Specimen Type Temperature Time
Tissue Varies

Reject Due To








Specimen in formalin or fixative preservative

Reference Values

>0.10 nmol/min/mg Prot

Day(s) and Time(s) Performed


CPT Code Information


88233-Fibroblast culture

88240-Cryopreservation for biochemical studies

LOINC Code Information

Test ID Test Order Name Order LOINC Value
NEURF Neuraminidase, Fibroblasts 24099-4


Result ID Test Result Name Result LOINC Value
35033 Neuraminidase Activity 24099-4
32056 Interpretation (NEURF) 59462-2
34584 Reviewed By No LOINC Needed

Analytic Time

30-45 days depending on rapidity of growth


Specimens with activity more than 0.10 nmol/min/mg protein are considered to be normal.


Specimens with activity of  0.10 nmol/min/mg protein or less are considered to be abnormal and suggestive of neuraminidase deficiency. Molecular confirmation is recommended.


This test cannot discriminate carriers, hence it is not recommended for carrier screening


Neuraminidase is a particularly unstable enzyme and may be quickly destroyed by freezing, sonication, solubilization, and most purification procedures.

Method Description

Neuraminidase activity is measured by the hydrolysis of 4-methylumbelliferyl-alpha-D-N-acetylneuraminic acid producing 4-methylumbelliferone, which is measured fluorometrically.(Modified from O'Brein JS, Warner TG: Sialidosis: delineation of subtypes by neuraminidase assay. Clin Genet 1980;17:35-38)

Clinical Information

Sialidosis, also known as mucolipidosis I, is an autosomal recessive lysosomal storage disorder (LSD) resulting from an isolated deficiency of the enzyme neuraminidase. Clinical presentation can vary and phenotypes are typically categorized by age of onset. Type I is considered to be the milder form of sialidosis and is characterized by a cherry-red spot on the retina, progressive decreased acuity, impaired color vision, or night blindness. Neurologic problems include gait abnormalities and poorly controlled myoclonus. Type II sialidosis is distinguished from type I by the presence of dysmorphic features, including coarse facies, hepatosplenomegaly, and dysostosis multiplex, early age of onset, and its more rapid disease progression. Developmental delay is frequently present in type II sialidosis. The congenital form is typically associated with hydrops.


Galactosialidosis is an autosomal recessive lysosomal storage disease associated with a combined deficiency of neuraminidase and beta-galactosidase secondary to a defect in the cathepsin A protein. Clinical features are those typically associated with LSD including coarse facial features, cherry-red spots, and skeletal dysplasia. The disorder can be classified into 3 subtypes that vary with respect to age of onset and clinical presentation. The early infantile form is associated with fetal hydrops, visceromegaly, skeletal and ophthalmologic disorders, and early death. The late infantile form typically presents with short stature, dysostosis multiplex, coarse facial features, hepatosplenomegaly, and heart valve problems. The juvenile/adult form is characterized by progressive neurologic degeneration, ataxia, cognitive disability, and angiokeratomas. Most of the juvenile/adult onset cases have been found in individuals of Japanese ancestry. A diagnosis of galactosialidosis is obtained by demonstrating a combined deficiency of neuraminidase and beta-galactosidase in lymphocytes or cultured skin fibroblasts.

Specimen Retention Time

3 years - check with lab for availability

Disease States

  • Sialidosis

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.

Genetics Test Information

This test is not recommended for prenatal testing.


1. New York Clients-Informed consent is required. Please document on the request form or electronic order that a copy is on file. An Informed Consent for Genetic Testing (T576) is available in Special Instructions.

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