Preferred Sample Type

Purine Nucleoside Phosphorylase

Suitable Specimen Types

  • EDTA Whole Blood
5 mL

Specimen Transport

First Class Post. Send whole blood.

Sample Processing in Laboratory


Sample Preparation

Do not centrifuge.

Sample Stability


Purine Nucleoside Phosphorylase

General Information

Purine nucleoside phosphorylase deficiency, often called PNP-deficiency, is a rare autosomal recessive metabolic disorder which results in severe combined immunodeficiency.

The disorder is caused by a mutation of the purine nucleoside phosphorylase (PNP) gene, located at chromosome 14q13.1. PNP is a key enzyme in the purine salvage pathway, and is required for purine degradation. Specifically, it catalyzes the conversion of inosine and guanosine to hypoxanthine. A deficiency of it leads to build up of elevated deoxy-GTP (dGTP) levels resulting in T-cell toxicity and deficiency. In contrast to adenosine deaminase deficiency (another deficiency of purine metabolism), there is minimal disruption to B cells.

Patient Preparation



Mutation analysis and carrier screening

Reference Range

Provided by Reference Lab


  • EQA Status: In House

The laboratories at Heartlands Hospital, Good Hope Hospital and Solihull Hospital form part of the services provided by University Hospitals Birmingham and are UKAS (United Kingdom Accreditation Service) accredited to the ISO 15189:2012 standard. For a list of accredited tests and other information please visit the UKAS website using the following link:

  • Heartlands, Good Hope and Solihull Hospital pathology laboratories are a UKAS accredited medical laboratory No.8217
  • United Kingdom Health Security Agency laboratory is a UKAS accredited medical laboratory No.8213

Tests not appearing on the UKAS Schedule of Accreditation currently remain outside of our scope of accreditation. However, these tests have been validated to the same high standard as accredited tests and are performed by the same trained and competent staff.

For further test information, please visit the test database:

For further information contact Louise Fallon, Quality Manager, 0121 424 1235