TEST CATALOG ORDERING & RESULTS SPECIMEN HANDLING CUSTOMER SERVICE EDUCATION & INSIGHTS
Test Catalog

Test ID: PUPYP    
Purines and Pyrimidines Panel, Plasma

Useful For Suggests clinical disorders or settings where the test may be helpful

Evaluating patients with symptoms suspicious for disorders of purine and pyrimidine metabolism

 

Monitoring patients with disorders of purine and pyrimidine metabolism

 

Laboratory evaluation of primary and secondary hyperuricemias

 

Assessing tolerance for fluoropyrimidine drugs used in cancer treatment

 

Aiding in the diagnosis of individuals with suspected dihydropyrimidine dehydrogenase (DPD) deficiency

Genetics Test Information Provides information that may help with selection of the correct genetic test or proper submission of the test request

Purines and pyrimidines are key components in biological processes and required by all cells for growth and survival.

 

At least 35 known inherited disorders of purine and pyrimidine metabolism exist representing a diversity of neurological, immunological, hematological, and renal manifestations.

Testing Algorithm Delineates situations when tests are added to the initial order. This includes reflex and additional tests.

Clinical Information Discusses physiology, pathophysiology, and general clinical aspects, as they relate to a laboratory test

Purines (adenine, guanine, xanthine, hypoxanthine, uric acid) and pyrimidines (uracil, thymine, cytosine, orotic acid) are involved in all biological processes, providing the basis for storage, transcription, and translation of genetic information as RNA and DNA. Purines are required by all cells for growth and survival and also play a role in signal transduction and translation. Purines and pyrimidines originate primarily from endogenous synthesis, with dietary sources playing only a minor role. The end product of purine metabolism is uric acid (2,6,8-trioxypurine), which must be excreted continuously to avoid toxic accumulation.

 

Disorders of purine and pyrimidine metabolism can involve all organ systems at any age. The diagnosis of the specific disorders of purine and pyrimidine metabolism is based upon the clinical presentation of the patient, determination of specific concentration patterns of purine and pyrimidine metabolites, and confirmatory enzyme assays and molecular genetic testing.

 

Over 35 inborn errors of purine and pyrimidine metabolism have been documented. Clinical features are dependent upon the specific disorder but represent a broad spectrum of clinical manifestations that may include immunodeficiency, developmental delay, nephropathy, and neurologic involvement. The most commonly described disorder of purine metabolism involves a deficiency of hypoxanthine-guanine phosphoribosyl transferase (HPRT), the majority of which have classic Lesch-Nyhan syndrome. Lesch-Nyhan syndrome is an X-linked disorder characterized by crystals in urine, neurologic impairment, mild to severe intellectual disability, development of self-injurious behavior, and uric acid nephropathy.

 

Treatments for Lesch-Nyhan syndrome include allopurinol, urine alkalinization and hydration for nephropathy, and supportive management of neurologic symptoms. For milder forms of HPRT deficiency, treatment that can mitigate the potentially devastating effects of these diseases are disorder dependent; therefore, early recognition through screening and subsequent confirmatory testing is highly desirable.

 

Dihydropyrimidine dehydrogenase (DPD) deficiency  can result in a severe disorder in infancy involving seizures, intellectual disability, microcephaly and hypertonia. In its mildest form however, individuals with DPD deficiency may be asymptomatic but are at risk for life-threatening toxic reactions to a certain class of drugs used to treat cancer called fluoropyrimidines (eg, 5-fluorouracil and capecitabine). If individuals with DPD deficiency ingest this medication, they can develop fluoropyrimidine toxicity. This drug toxicity can result in inflammation of the gastrointestinal tract and associated symptoms, as well as abnormal blood counts including neutropenia and thrombocytopenia.

Reference Values Describes reference intervals and additional information for interpretation of test results. May include intervals based on age and sex when appropriate. Intervals are Mayo-derived, unless otherwise designated. If an interpretive report is provided, the reference value field will state this.

Purines and Pyrimidines Pane, Plasmal

Reference Values

(all results reported as nmol/mL)

Age range

0-1 years

>1-4 years

5-18 years

>18 years

Uracil

< or =2

< or =2

< or =2

< or =2

Thymine

< or =2

< or =2

< or =2

< or =2

Adenine

< or =3

< or =3

< or =3

< or =3

Hypoxanthine

< or =35

< or =17

< or =15

< or =15

Xanthine

< or =6

< or =6

< or =6

< or =3

Dihydroorotic

< or =2

< or =2

< or =2

< or =2

Uric Acid

100-450

150-500

150-500

150-500

Deoxythymidine

< or =2

< or =2

< or =2

< or =2

Deoxyuridine

< or =2

< or =2

< or =2

< or =2

Uridine

< or =14

< or =9

< or =9

< or =9

Deoxyinosine

< or =2

< or =2

< or =2

< or =2

Deoxyguanosine

< or =2

< or =2

< or =2

< or =2

Inosine

< or =2

< or =2

< or =2

< or =2

Guanosine

< or =2

< or =2

< or =2

< or =2

Dihydrouracil

< or =3

< or =3

< or =3

< or =3

Dihydrothymine

< or =2

< or =2

< or =2

< or =2

N-carbamoyl- beta-alanine

< or =2

< or =2

< or =2

< or =2

N-carbamoyl- beta-aminoisobutryic acid

< or =2

< or =2

< or =2

< or =2

Interpretation Provides information to assist in interpretation of the test results

Abnormal concentrations of measurable compounds will be reported along with an interpretation. The interpretation of an abnormal metabolite pattern includes an overview of the results and of their significance, a correlation to available clinical information, possible differential diagnosis, recommendations for additional biochemical testing and confirmatory studies (enzyme assay, molecular analysis), name, and phone number of contacts who may provide these studies, and a phone number of the laboratory directors in case the referring physician has additional questions.

Cautions Discusses conditions that may cause diagnostic confusion, including improper specimen collection and handling, inappropriate test selection, and interfering substances

Additional confirmatory testing is required for follow-up of abnormal results.

Clinical Reference Recommendations for in-depth reading of a clinical nature

1. Jinnah HA, Friedmann T: Lesch-Nyhan disease and its variants. In: Valle D, Antonarakis S, Ballabio A, Beaudet AL, Mitchell GA, eds. The Online Metabolic and Molecular Bases of Inherited Disease. McGraw-Hill; 2019. Accessed November 23, 2020. Available at https://ommbid.mhmedical.com/content.aspx?sectionid=225089443

2. Balasubramaniam S, Duley JA, Christodoulou J: Inborn errors of purine metabolism: clinical update and therapies. J Inherit Metab Dis. 2014;37:669-686

3. Balasubramaniam S, Duley JA, Christodoulou J: Inborn errors of pyrimidine metabolism: clinical update and therapy. J Inherit Metab Dis. 2014;37:687-698

Special Instructions Library of PDFs including pertinent information and forms related to the test