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Test ID: SUAC Succinylacetone, Blood Spot

Reporting Name

Succinylacetone, BS

Useful For

Second-tier newborn screening for tyrosinemia type 1 (Tyr 1) in blood spots with nonspecific elevations of tyrosine


Diagnosis of Tyr 1


Follow-up of patients with Tyr 1

Specimen Type

Whole blood

Specimen Required

Supplies: Card - Blood Spot Collection (Filter Paper) (T493)

Container/Tube: Local Newborn Screening Card

Specimen Volume: 2 blood spots

Collection Instructions:

1. Do not use device or capillary tube containing EDTA to collect specimen.

2. At least 1 spot should be complete, ie, unpunched.

3. Do not expose specimen to heat or direct sunlight.

4. Do not stack wet specimens.

5. Keep specimen dry.

6. If collection of a new specimen is necessary, let blood dry on the Blood Spot Collection Card (T493) at ambient temperature in a horizontal position for 3 hours.

Additional Information:

1. For collection instructions in Spanish, see Blood Spot Collection Card-Spanish Instructions (T777) in Special Instructions.

2. For collection instructions in Chinese, see Blood Spot Collection Card-Chinese Instructions (T800) in Special Instructions.

Specimen Minimum Volume

Blood Spot: 1

Specimen Stability Information

Specimen Type Temperature Time
Whole blood Ambient (preferred)

Reference Values

An interpretive report will be provided.

Day(s) and Time(s) Performed

Monday, Wednesday, Friday; 9 a.m.

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.

CPT Code Information


LOINC Code Information

Test ID Test Order Name Order LOINC Value
SUAC Succinylacetone, BS 53231-7


Result ID Test Result Name Result LOINC Value
22713 Results 53231-7
22714 Interpretation 59462-2
22716 Reviewed By 18771-6

Clinical Information

Tyrosinemia type 1 (Tyr 1) is an autosomal recessive condition caused by fumarylacetoacetate hydrolase (FAH) deficiency. Tyr 1 can cause severe liver disease, hypophosphatemic rickets, renal tubular dysfunction, and neurologic crises. If left untreated, most patients die of liver failure in the first years of life. Treatment with 2-(2-nitro-4-trifluoromethylbenzoyl)-1,3 cyclohexanedione is available and is particularly effective when initiated in newborns. The incidence of Tyr 1 is approximately 1 in 100,000 live births.


While tyrosine can be determined by routine newborn screening, it is not a specific marker for Tyr I and often may be associated with common and benign transient tyrosinemia of the newborn. Succinylacetone (SUAC) is a specific marker for Tyr I, but is not detectable by routine newborn screening. This assay determines SUAC in newborn blood spots by tandem mass spectrometry. Additional follow-up testing may include confirmatory molecular analysis of the FAH gene.


Normal: <5.0 mcM


Elevations of succinylacetone (SUAC) above the reference range are indicative of tyrosinemia type 1 (Tyr 1).


Patients with Tyr I who are treated with diet and/or 2-(2-nitro-4-trifluoromethylbenzoyl)-1,3 cyclohexanedione (nitisinone) should have declining or normal values of SUAC.

Clinical Reference

1. Larochelle J, Alvarez F, Bussieres JF, et al: Effects of nitisinone (NTBC) treatment on the clinical course of hepatorenal tyrosinemia in Quebec. Mol Genet Metab 2012;107(1-2):49-54

2. Mitchell GA, Grompe M, Lambert M, Tanguay RM: Hypertyrosinemia. In The Metabolic and Molecular Bases of Inherited Disease. Eighth edition. Edited by CR Scriver, AL Beaudet, WS Sly, et al. New York, McGraw-Hill Book Company, 2001, pp 1777-1805

3. De Jesus VR, Adam BW, Mandel D, et al: Succinylacetone as primary marker to detect tyrosinemia type I in newborns and its measurement by newborn screening programs. Mol Genet Metab 2014;113(1-2)67-75

Analytic Time

3 days

Method Name

Flow Injection Analysis-Tandem Mass Spectrometry (MS/MS)


If not ordering electronically, complete, print, and send an Inborn Errors of Metabolism Test Request (T798) with the specimen.

Mayo Clinic Laboratories | Genetics and Pharmacogenomics Catalog Additional Information: