Pathology Handbook

White cell enzymes

Synonyms

Lysosomal storage disease test

Clinical Indications

Many metabolic diseases are caused by an enzyme defect which can be detected in the white cells:

(a) The lysosomal storage disorders present with a variety of symptoms and various white cell enzyme screens are available according to the presenting symptoms. It is important that full clinical details accompany the samples in order that an appropriate screen is carried out

1) Full Neurological screen (patients under 16 yrs) for neurodegenerative disorders, e.g. neurological regression, fits, hypotonia

2) Dysmorphic screen: The first line test for a dysmorphic child is screening for a mucopolysaccharidosis by urine GAGs

3) Storage disorders screen

4) Cherry red spot screen: for patients with a cherry red spot on the macula

5) Angiokeratoma screen 

(b) Other specific white cell enzymes may be requested according to the disease to be excluded

1. Mucopolysaccharidoses

2. Mucolipidoses

3. Gangliosidoses

4. Leucodystrophies

5. Neuronal Ceroid Lipofuscinoses

6. Glycoprotein storage disorders

Test Includes

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Part of Profile

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Request Form 

Request on ICE

Full clinical details must be given so that the appropriate tests care carried out

Availability

Analysed by referral laboratory if specific criteria met.

Specific Criteria

Requested by Consultant Paediatricians or if agreed with Consultant Biochemist

Patient Preparation

Blood transfusion within the last 4 weeks may invalidate the test

Samples must only be collected on Monday to Thursday

Turnaround Time

4 - 6 weeks

Specimen

Whole Blood in green top lithium heparin tube

Volume

At least 5 mL; 10 mL is preferable

Container

Vacutainer green top

Collection

Samples must be collected before 10.30am and must be transported to laboratory immediately.

Samples must only be collected on Monday to Thursday

Causes for Rejection

Unlabelled sample
Not meeting specific criteria for analysis. 
Delay in sample reaching laboratory

Received after 10.30h or on a Friday 

Reference Range

See laboratory report