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DPYD Genotyping

Test Number 512275
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CPT

81232
Synonyms
  • Dihydropyrimidine Dehydrogenase
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  • Updated on 05/28/2026

Test Details

Methodology

DNA analysis is performed by allele-specific real-time polymerase chain reaction (PCR) to detect specific single-nucleotide polymorphisms (SNPs) or small insertions/deletions within the DPYD gene. DPYD genetic variants detected by this assay include all Tier 1 and Tier 2 variants recommended for clinical testing by the Association for Molecular Pathology (AMP).

"Reference" is used to indicate that no variants tested were detected. The activity score (AS) assigned to a Reference result is 1. Decreased function variants are assigned an AS of 0.5. Non-functional variants are assigned an AS of 0.

DNA analysis is performed by allele-specific real-time polymerase chain reactions (RT-PCR) to detect single-nucleotide polymorphisms (SNPs) within the DPYD gene and to assign variant DPYDc.1905+1G>A (previously *2A, rs3918290), c.1679T>G (previously *13, rs55886062), c.2846A>T (rs67376798), c.1236G>A (in HapB3 with c.1129-5923C>G, rs56038477), and c.557A>G (rs115232898) alleles. Reference denotes detection of the wild-type sequence at the assessed positions. No other variants in this gene are detected by this assay.

DNA analysis is performed by allele-specific real-time polymerase chain reaction (PCR) to detect specific single-nucleotide polymorphisms (SNPs) or small insertions/deletions within the DPYD gene. DPYD genetic variants detected by this assay include all Tier 1 and Tier 2 variants recommended for clinical testing by the Association for Molecular Pathology (AMP).

"Reference" is used to indicate that no variants tested were detected. The activity score (AS) assigned to a Reference result is 1. Decreased function variants are assigned an AS of 0.5. Non-functional variants are assigned an AS of 0.

Result Turnaround Time

7 - 10 days

Turnaround time is defined as the usual number of days from the date of pickup of a specimen for testing to when the result is released to the ordering provider. In some cases, additional time should be allowed for additional confirmatory or additional reflex tests. Testing schedules may vary.

Related Documents

For more information, please view the literature below.

For more information, please view the literature below.

For more information, please view the literature below.

Use

Assay background: This assay detects genetic variants in the dihydropyrimidine dehydrogenase (DPYD) gene. The list of variants included in the assay is shown below. The DPYD gene encodes the dihydropyrimidine dehydrogenase (DPD) enzyme. The DPD enzyme metabolizes fluoropyrimidine drugs including 5 fluorouracil (5-FU) and capecitabine; these drugs are frequently used as chemotherapeutic agents for colorectal cancer and other solid tumors.

Result interpretation:

Reference/Reference result interpretation: Normal DPD enzyme activity is predicted because no variants tested in this assay were identified in this individual. Individuals with normal DPD enzyme activity are known as normal metabolizers and are considered to have  an enzyme activity score (AS) of 2. When fluoropyrimidine drugs are administered to individuals with normal DPD enzyme activity, the drugs are efficiently broken down to inactive metabolites.

Any variant/Reference result interpretation: Partial DPD enzyme deficiency is predicted because this individual is positive for one DPYD genetic variant. Individuals with decreased DPD enzyme activity are known as intermediate metabolizers. The enzyme activity score (AS) can be 1 or 1.5 depending on the variant identified in this individual. This individual's total AS can be calculated as the sum of 1 (AS for Reference) plus the AS of the variant provided in the list of variants below. Intermediate metabolizers are found in approximately 3-8% of the population.

Any variant/Any variant result interpretation: Partial or Complete DPD enzyme deficiency is predicted because this individual is positive for two DPYD genetic variants. Individuals with partial DPD enzyme activity are known as intermediate metabolizers, and those with complete DPD deficiency are known as poor metabolizers. The enzyme activity scores (AS) for the variants identified in this individual are provided in the list of variants below. This individual's total AS can be calculated as the sum of the AS of both variants. An AS of 1 would predict an Intermediate metabolizer. An AS of 0 or 0.5 would predict a Poor metabolizer, representing less than 0.5% of the population.

When fluoropyrimidine drugs are administered in standard doses to individuals with partial or complete DPD enzyme deficiency, there may be a buildup of fluoropyrimidines that may lead to severe or lethal toxicity. In these individuals, information about predicted metabolic activity and activity scores can aid in determining a therapeutic strategy for drugs that are metabolized by DPD. Extensive evidence supports the use of DPYD genotyping for guiding fluoropyrimidine usage and dosing and reducing the risk of toxicity. 

List of variants detected in this assay with alternate variant names and associated activity scores (AS):

  • c.299_302del (*7, rs72549309, AS = 0)
  • c.557A>G (rs115232898, AS = 0.5)
  • c.703C>T (*8, rs1801266, AS = 0)
  • c.868A>G (rs146356975, AS = 0.5)
  • c.1129-5923C>G (HapB3, rs75017182, AS = 0.5). This variant (decreased activity) was previously assumed to be always on the same chromosome as the c.1236G>A variant (normal activity). For this reason, c.1236G>A has been widely used as a surrogate for c.1129-5923C>G. However, recent data show that the two variants are not always on the same chromosome: rarely, c.1236G>A can be seen in the absence of c.1129-5923C>G. If both variants are detected in this assay only the c.1129-5923C>G is reported. If only the c.1236G>A variant is detected it is reported as a normal (Reference) variant.
  • c.1236G>A (HapB3, rs56038477, AS = 1). Reported as normal in rare instances when the decreased function variant c.1129-5923C>G is not present. When c.1129-5923C>G is also present or when c.1129-5923C>G is not tested, AS is inferred to be 0.5.
  • c.1314T>G (rs186169810, AS = 0.5)
  • c.1475C>T (rs72549304, AS = 0)
  • c.1679T>G (*13, rs55886062, AS = 0)
  • c.1774C>T (rs59086055, AS = 0)
  • c.1905+1G>A (*2A, rs3918290, AS = 0)
  • c.2279C>T (rs112766203, AS = 0.5)
  • c.2639G>T (rs55674432, AS = 0)
  • c.2846A>T (rs67376798, AS = 0.5)
  • Reference (AS = 1): No variant, normal function

 

The dihydropyrimidine dehydrogenase gene (DPYD) produces a drug-metabolizing enzyme, dihydropyrimidine dehydrogenase (DPD), which is involved in the metabolism of several clinically important drugs including the fluoropyrimidines 5-fluorouracil and capecitabine, which are frequently used as chemotherapeutic drugs. Individuals with some variant DPYD alleles are at increased risk for side effects from drugs that are metabolized by DPD. DPYD genotype information can be utilized to predict DPD metabolic activity, which can be used as an aid in determining a therapeutic strategy for drugs that are metabolized by DPD. For example, DPD eliminates over 80% of the drug 5-fluoracil. An intermediate or poor metabolizer may be subjected to a buildup of 5-fluoracil, which can be associated with severe toxicity. Substantial evidence supports the use of DPYD genotyping for guiding fluoropyrimidine dosage/use.

Variation in the DPYD gene can result in normal (NM), intermediate (IM) and poor (PM) drug-metabolizing genotypes. In general, relative to the reference sequence (normal function), c.2846A>T (rs67376798), c.1236G>A (in HapB3 with c. 1129-5923C>G, rs56038477) and c.557A>G (rs115232898), variants have decreased function while c.1905+1G>A (previously *2A, rs3918290) and c.1679T>G (previously *13, rs55886062) variants have no function.

Assay background: This assay detects genetic variants in the dihydropyrimidine dehydrogenase (DPYD) gene. The list of variants included in the assay is shown below. The DPYD gene encodes the dihydropyrimidine dehydrogenase (DPD) enzyme. The DPD enzyme metabolizes fluoropyrimidine drugs including 5 fluorouracil (5-FU) and capecitabine; these drugs are frequently used as chemotherapeutic agents for colorectal cancer and other solid tumors.

Result interpretation:

Reference/Reference result interpretation: Normal DPD enzyme activity is predicted because no variants tested in this assay were identified in this individual. Individuals with normal DPD enzyme activity are known as normal metabolizers and are considered to have  an enzyme activity score (AS) of 2. When fluoropyrimidine drugs are administered to individuals with normal DPD enzyme activity, the drugs are efficiently broken down to inactive metabolites.

Any variant/Reference result interpretation: Partial DPD enzyme deficiency is predicted because this individual is positive for one DPYD genetic variant. Individuals with decreased DPD enzyme activity are known as intermediate metabolizers. The enzyme activity score (AS) can be 1 or 1.5 depending on the variant identified in this individual. This individual's total AS can be calculated as the sum of 1 (AS for Reference) plus the AS of the variant provided in the list of variants below. Intermediate metabolizers are found in approximately 3-8% of the population.

Any variant/Any variant result interpretation: Partial or Complete DPD enzyme deficiency is predicted because this individual is positive for two DPYD genetic variants. Individuals with partial DPD enzyme activity are known as intermediate metabolizers, and those with complete DPD deficiency are known as poor metabolizers. The enzyme activity scores (AS) for the variants identified in this individual are provided in the list of variants below. This individual's total AS can be calculated as the sum of the AS of both variants. An AS of 1 would predict an Intermediate metabolizer. An AS of 0 or 0.5 would predict a Poor metabolizer, representing less than 0.5% of the population.

When fluoropyrimidine drugs are administered in standard doses to individuals with partial or complete DPD enzyme deficiency, there may be a buildup of fluoropyrimidines that may lead to severe or lethal toxicity. In these individuals, information about predicted metabolic activity and activity scores can aid in determining a therapeutic strategy for drugs that are metabolized by DPD. Extensive evidence supports the use of DPYD genotyping for guiding fluoropyrimidine usage and dosing and reducing the risk of toxicity. 

List of variants detected in this assay with alternate variant names and associated activity scores (AS):

  • c.299_302del (*7, rs72549309, AS = 0)
  • c.557A>G (rs115232898, AS = 0.5)
  • c.703C>T (*8, rs1801266, AS = 0)
  • c.868A>G (rs146356975, AS = 0.5)
  • c.1129-5923C>G (HapB3, rs75017182, AS = 0.5). This variant (decreased activity) was previously assumed to be always on the same chromosome as the c.1236G>A variant (normal activity). For this reason, c.1236G>A has been widely used as a surrogate for c.1129-5923C>G. However, recent data show that the two variants are not always on the same chromosome: rarely, c.1236G>A can be seen in the absence of c.1129-5923C>G. If both variants are detected in this assay only the c.1129-5923C>G is reported. If only the c.1236G>A variant is detected it is reported as a normal (Reference) variant.
  • c.1236G>A (HapB3, rs56038477, AS = 1). Reported as normal in rare instances when the decreased function variant c.1129-5923C>G is not present. When c.1129-5923C>G is also present or when c.1129-5923C>G is not tested, AS is inferred to be 0.5.
  • c.1314T>G (rs186169810, AS = 0.5)
  • c.1475C>T (rs72549304, AS = 0)
  • c.1679T>G (*13, rs55886062, AS = 0)
  • c.1774C>T (rs59086055, AS = 0)
  • c.1905+1G>A (*2A, rs3918290, AS = 0)
  • c.2279C>T (rs112766203, AS = 0.5)
  • c.2639G>T (rs55674432, AS = 0)
  • c.2846A>T (rs67376798, AS = 0.5)
  • Reference (AS = 1): No variant, normal function

 

Limitations

This test cannot determine whether DPYD variants detected are on the same chromosome. Individuals negative for tested variants may have rare DPYD variant(s) associated with increased risk of fluoropyrimidine-related toxicity that are not detected by this assay. The exact effect of a particular genetic result on individual drugs can vary. Results do not rule out the possibility of other genetic variants in DPYD or in genes associated with other drug metabolism pathways. Molecular-based testing is highly accurate, but as in any laboratory test, rare diagnostic errors may occur. 

In addition to the genetic findings, the metabolism of drugs may be influenced by factors that include environment, diet and medications; these factors and others should be considered prior to initiating a new therapy. All results should be interpreted in the context of other test results and clinical findings. 

This test was developed and its performance characteristics determined by Labcorp. It has not been cleared or approved by the Food and Drug Administration.

The exact effect of a particular genotype on individual drugs can vary. In addition to genotype, the metabolism of drugs may be influenced by additional factors that include environmental, dietary and other medications; these factors and others should be considered prior to initialing a new therapy. All results must be interpreted in the context of other test results and clinical findings. Results do not rule out the possibility of other variant alleles in DPYD or other variant alleles in other drug metabolism pathways. Patients should speak with their health care provider about the individual results of this test.

Molecular-based testing is highly accurate, but as in any laboratory test, rare diagnostic errors may occur.

This test was developed and its performance characteristics determined by Labcorp. It has not been cleared or approved by the Food and Drug Administration.

This test cannot determine whether DPYD variants detected are on the same chromosome. Individuals negative for tested variants may have rare DPYD variant(s) associated with increased risk of fluoropyrimidine-related toxicity that are not detected by this assay. The exact effect of a particular genetic result on individual drugs can vary. Results do not rule out the possibility of other genetic variants in DPYD or in genes associated with other drug metabolism pathways. Molecular-based testing is highly accurate, but as in any laboratory test, rare diagnostic errors may occur. 

In addition to the genetic findings, the metabolism of drugs may be influenced by factors that include environment, diet and medications; these factors and others should be considered prior to initiating a new therapy. All results should be interpreted in the context of other test results and clinical findings. 

This test was developed and its performance characteristics determined by Labcorp. It has not been cleared or approved by the Food and Drug Administration.

Specimen Requirements

Specimen

Whole blood or Labcorp buccal swab kit (buccal swab collection kit contains 4 swabs and instructions for use of a buccal swab)

Volume

2 mL whole blood or one buccal swab kit (4 swabs)

Minimum Volume

1 mL whole blood or two buccal swabs

Container

Lavender-top (EDTA) tube or yellow-top (ACD) tube or Labcorp buccal swab kit

Collection Instructions

Collect specimen in a lavender-top (EDTA) or yellow-top (ACD) tube, or use a buccal swab kit (4 swabs). Ship whole blood specimen at room temperature or frozen. Ship buccal swab kit at room temperature.

Stability Requirements

TemperaturePeriod
Room temperature

Whole Blood: 28 days

Swabs: 2 Months

Refrigerated

Whole Blood: 28 days

Swabs: Unstable

Frozen

Whole Blood: 2 years

Swabs: Unstable

Storage Instructions

Maintain whole blood specimen at room temperature or refrigerated for 28 days or frozen for 2 years. Maintain buccal swabs at room temperature for 2 months.

Causes for Rejection

Quantity not sufficient for analysis; improper container; single buccal swab; wet buccal swab; buccal swabs without outer collection envelope; severely damaged buccal swab envelope; buccal swab envelope received open; frozen glass tube

References

Amstutz U, Henricks LM, Offer SM, et al. Clinical Pharmacogenetis Implementation Consortium (CPIC) Guideline for Dihydropyrimidine Dehydorgenase Genotype and Fluoropyrimidine Dosing: 2017 Update. Clin Pharmacol Ther. 2018 Feb;103(2):210-216. Epub 2017 Nov 20. PubMed 29152729

Clinical Pharmacogenetics Implementation Consortium (CPIC) Guideline for Fluoropyrimidines and DPYD: Updated January 2024. ClinPGx website: https://www.clinpgx.org/guideline/PA166251462. Updated January 2024. Accessed May 2025.

Dean L, Kane M. Fluorouracil Therapy and DPYD Genotype. In: Medical Genetics Summaries [Internet]. Bethesda (MD): National Center for Biotechnology Information (US); 2012. 2016 Nov 3 [updated 2025 Aug 14]. PubMed 28520376

National Comprehensive Cancer Network. NCCN Clinical Practice Guidelines in Oncology: Colon Cancer (Version 2.2025).

Pratt VM, Cavallari LH, Fulmer ML, et al. DPYD Genotyping Recommendations: A Joint Consensus Recommendation of the Association for Molecular Pathology, American College of Medical Genetics and Genomics, Clinical Pharmacogenetics Implementation Consortium, College of American Pathologists, Dutch Pharmacogenetics Working Group of the Royal Dutch Pharmacists Association, European Society for Pharmacogenomics and Personalized Therapy, Pharmacogenomics Knowledgebase, and Pharmacogene Variation Consortium. J Mol Diagn. 2024 Oct;26(10):851-863. PubMed 39032821

US Food and Drug Administration (FDA). Table of Pharmacogenetic Associations. FDA website: https://www.fda.gov/medical-devices/precision-medicine/table-pharmacogenetic-associations. Updated October 26, 2022. Accessed May 2023.
Amstutz U, Henricks LM, Offer SM, et al. Clinical Pharmacogenetis Implementation Consortium (CPIC) Guideline for Dihydropyrimidine Dehydorgenase Genotype and Fluoropyrimidine Dosing: 2017 Update. Clin Pharmacol Ther. 2018 Feb;103(2):210-216. Epub 2017 Nov 20.29152729
Caudle KE, Thorn DF, Klein TS, et al. Clinical Pharmacogenetics Implementation Consortium guidelines for dihydropyrimidine dehydrogenase genotype and fluoropyrimidine dosing. Clin Pharmacol Ther. 2013 Dec;94(6):640-645.23988873
Morel A, Boisdon CM, Fey L, et al. Clinical relevance of different dihydropyrimidine dehydrogenase gene single nucleotide polymorphisms on 5-fluorouracil tolerance. Mol Cancer Ther. 2006 Nov;5(11):2895-2904.17121937
US Food and Drug Administration (FDA). Table of Pharmacogenetic Associations. FDA website: https://www.fda.gov/medical-devices/precision-medicine/table-pharmacogenetic-associations. Updated October 26, 2022. Accessed May 2023.

Amstutz U, Henricks LM, Offer SM, et al. Clinical Pharmacogenetis Implementation Consortium (CPIC) Guideline for Dihydropyrimidine Dehydorgenase Genotype and Fluoropyrimidine Dosing: 2017 Update. Clin Pharmacol Ther. 2018 Feb;103(2):210-216. Epub 2017 Nov 20. PubMed 29152729

Clinical Pharmacogenetics Implementation Consortium (CPIC) Guideline for Fluoropyrimidines and DPYD: Updated January 2024. ClinPGx website: https://www.clinpgx.org/guideline/PA166251462. Updated January 2024. Accessed May 2025.

Dean L, Kane M. Fluorouracil Therapy and DPYD Genotype. In: Medical Genetics Summaries [Internet]. Bethesda (MD): National Center for Biotechnology Information (US); 2012. 2016 Nov 3 [updated 2025 Aug 14]. PubMed 28520376

National Comprehensive Cancer Network. NCCN Clinical Practice Guidelines in Oncology: Colon Cancer (Version 2.2025).

Pratt VM, Cavallari LH, Fulmer ML, et al. DPYD Genotyping Recommendations: A Joint Consensus Recommendation of the Association for Molecular Pathology, American College of Medical Genetics and Genomics, Clinical Pharmacogenetics Implementation Consortium, College of American Pathologists, Dutch Pharmacogenetics Working Group of the Royal Dutch Pharmacists Association, European Society for Pharmacogenomics and Personalized Therapy, Pharmacogenomics Knowledgebase, and Pharmacogene Variation Consortium. J Mol Diagn. 2024 Oct;26(10):851-863. PubMed 39032821

US Food and Drug Administration (FDA). Table of Pharmacogenetic Associations. FDA website: https://www.fda.gov/medical-devices/precision-medicine/table-pharmacogenetic-associations. Updated October 26, 2022. Accessed May 2023.

LOINC® Map

Order Code Order Code Name Order Loinc Result Code Result Code Name UofM Result LOINC
512275 DPYD Genotyping 93199-8 512273 DPYD Genotype 93199-8
512275 DPYD Genotyping 93199-8 512274 DPYD Metabolic Activity 79719-1
512275 DPYD Genotyping 93199-8 512276 Director Review 69426-5
512275 DPYD Genotyping 93199-8 512277 Interpretation 56850-1
512275 DPYD Genotyping 93199-8 512278 DPYD Information 55752-0
512275 DPYD Genotyping 93199-8 000000 MGRM Informed Consent Review 8262-8
Order Code512275
Order Code NameDPYD Genotyping
Order Loinc93199-8
Result Code512273
Result Code NameDPYD Genotype
UofM
Result LOINC93199-8
Order Code512275
Order Code NameDPYD Genotyping
Order Loinc93199-8
Result Code512274
Result Code NameDPYD Metabolic Activity
UofM
Result LOINC79719-1
Order Code512275
Order Code NameDPYD Genotyping
Order Loinc93199-8
Result Code512276
Result Code NameDirector Review
UofM
Result LOINC69426-5
Order Code512275
Order Code NameDPYD Genotyping
Order Loinc93199-8
Result Code512277
Result Code NameInterpretation
UofM
Result LOINC56850-1
Order Code512275
Order Code NameDPYD Genotyping
Order Loinc93199-8
Result Code512278
Result Code NameDPYD Information
UofM
Result LOINC55752-0
Order Code512275
Order Code NameDPYD Genotyping
Order Loinc93199-8
Result Code000000
Result Code NameMGRM Informed Consent Review
UofM
Result LOINC8262-8