Test Id : PBALP
Porphobilinogen and Aminolevulinic Acid, Plasma
Useful For
Suggests clinical disorders or settings where the test may be helpful
An equivalent option to urine for first-line test for evaluation of a suspected acute porphyria
Monitoring patients undergoing treatment for an acute intermittent porphyria or other acute porphyria
Genetics Test Information
Provides information that may help with selection of the correct genetic test or proper submission of the test request
Plasma porphobilinogen and aminolevulinic acid (ALA) are elevated during the symptomatic phase of the acute porphyrias: acute intermittent porphyria (AIP), hereditary coproporphyria, and variegate porphyria.
An isolated elevation of ALA may be due to the very rare ALA dehydratase deficiency porphyria (ADP) or more commonly, a secondary inhibition of ALA dehydratase.
This test can be used as part of the diagnostic assessment and monitoring of patients with AIP and other acute porphyrias.
If ordered for diagnostic purposes, results are most informative when the specimen is obtained while the patient is having symptoms.
Additional testing must be performed to distinguish among the acute porphyrias.
Highlights
This test is an alternative for the evaluation of a suspected acute porphyria when a urine specimen cannot be obtained during a symptomatic episode.
Testing Algorithm
Delineates situations when tests are added to the initial order. This includes reflex and additional tests.
Method Name
A short description of the method used to perform the test
Liquid Chromatography Tandem Mass Spectrometry (LC-MS/MS)
NY State Available
Indicates the status of NY State approval and if the test is orderable for NY State clients.
Reporting Name
Lists a shorter or abbreviated version of the Published Name for a test
Aliases
Lists additional common names for a test, as an aid in searching
5-Aminolevulinic Acid
Aminolevulinic Acid (ALA)
Acute Intermittent Porphyria (AIP)
ALA Dehydratase Deficiency Porphyria (ADP)
Delta-Aminolevulinic Acid
Hereditary Coproporphyria (HCP)
Variegate Porphyria (VP)
PBG (Porphobilinogen)
Testing Algorithm
Delineates situations when tests are added to the initial order. This includes reflex and additional tests.
Specimen Type
Describes the specimen type validated for testing
Plasma
Shipping Instructions
Ship specimens refrigerated or frozen and in amber vial to protect from light.
Necessary Information
Include a list of medications the patient is currently taking.
Specimen Required
Defines the optimal specimen required to perform the test and the preferred volume to complete testing
Patient Preparation: Patient must not consume any alcohol for at least 24 hours prior to specimen collection.
Supplies: Amber Frosted Tube, 5mL (T915)
Collection Container/Tube:
Preferred: Green top (sodium heparin)
Acceptable: Green top (lithium heparin), lavender top (EDTA), yellow top (ACD A or B)
Submission Container/Tube: Amber vial
Specimen Volume: 1 mL
Collection Instructions:
1. It is recommended that specimen collection occur during the acute phase. Porphobilinogen and aminolevulinic acid may be normal when the patient is not exhibiting symptoms.
2. Centrifuge and aliquot plasma into plastic vial.
Special Instructions
Library of PDFs including pertinent information and forms related to the test
Forms
If not ordering electronically, complete, print, and send a Biochemical Genetics Test Request (T798) with the specimen.
Specimen Minimum Volume
Defines the amount of sample necessary to provide a clinically relevant result as determined by the testing laboratory. The minimum volume is sufficient for one attempt at testing.
0.3 mL
Reject Due To
Identifies specimen types and conditions that may cause the specimen to be rejected
| Gross hemolysis | OK |
| Gross lipemia | OK |
| Gross icterus | OK |
Specimen Stability Information
Provides a description of the temperatures required to transport a specimen to the performing laboratory, alternate acceptable temperatures are also included
| Specimen Type | Temperature | Time | Special Container |
|---|---|---|---|
| Plasma | Frozen (preferred) | 21 days | LIGHT PROTECTED |
| Refrigerated | 7 days | LIGHT PROTECTED |
Useful For
Suggests clinical disorders or settings where the test may be helpful
An equivalent option to urine for first-line test for evaluation of a suspected acute porphyria
Monitoring patients undergoing treatment for an acute intermittent porphyria or other acute porphyria
Genetics Test Information
Provides information that may help with selection of the correct genetic test or proper submission of the test request
Plasma porphobilinogen and aminolevulinic acid (ALA) are elevated during the symptomatic phase of the acute porphyrias: acute intermittent porphyria (AIP), hereditary coproporphyria, and variegate porphyria.
An isolated elevation of ALA may be due to the very rare ALA dehydratase deficiency porphyria (ADP) or more commonly, a secondary inhibition of ALA dehydratase.
This test can be used as part of the diagnostic assessment and monitoring of patients with AIP and other acute porphyrias.
If ordered for diagnostic purposes, results are most informative when the specimen is obtained while the patient is having symptoms.
Additional testing must be performed to distinguish among the acute porphyrias.
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
The porphyrias are a group of inherited disorders resulting from enzyme defects in the heme biosynthetic pathway. Depending on the specific enzyme involved, various porphyrins and their precursors accumulate in different specimen types. The patterns of porphyrin accumulation in erythrocytes and plasma and the excretion of the heme precursors in urine and feces allow for the detection and differentiation of the porphyrias.
The porphyrias are typically classified as erythropoietic or hepatic based upon the primary site of the enzyme defect. In addition, of the 5 hepatic porphyrias, 4 typically present with acute neurological manifestations and are designated the acute porphyrias. Clinically, however, these attacks can be prolonged and chronic.
Three primary acute hepatic porphyrias: acute intermittent porphyria (AIP), hereditary coproporphyria (HCP), and variegate porphyria (VP), are associated with neurovisceral symptoms that typically onset during puberty or later. Common symptoms include severe abdominal pain, peripheral neuropathy, and psychiatric symptoms. A broad range of medications (including barbiturates and sulfa drugs), alcohol, infection, starvation, heavy metals, and hormonal changes may precipitate crises. Photosensitivity is not associated with AIP but may be present in HCP and VP.
Plasma porphobilinogen (PBG) and aminolevulinic acid (ALA) are elevated during the acute phase of these neurologic porphyrias. Urine and fecal porphyrin analysis should be performed to confirm the diagnosis and to distinguish among AIP, HCP, and VP. A biochemical diagnosis of AIP can be confirmed by measurement of PBG deaminase activity (PBGD_ / Porphobilinogen Deaminase, Whole Blood). VP and HCP can be confirmed by measurement of fecal porphyrins (FQPPS / Porphyrins, Feces). Once the biochemical diagnosis of an acute porphyria is established, molecular genetic testing is available (APGP / Acute Porphyria Gene Panel, Varies), which allows for diagnosis of at-risk family members.
The very rare (<10 cases described) autosomal recessive ALA dehydratase deficiency porphyria (ADP) is also a primary acute porphyria causing neurovisceral symptoms with variable age of onset. Biochemically, ADP is characterized by an isolated significant elevation of ALA. More commonly, however, isolated elevations of ALA are due to secondary inhibition of ALA dehydratase with acute lead intoxication, which results in the highest degree of aminolevulinic aciduria. Less significant elevations are seen in chronic lead intoxication, tyrosinemia type I, alcoholism, and pregnancy.
The workup of patients with a suspected porphyria is most effective when following a stepwise approach.
For more information, see the following or call 800-533-1710 to discuss testing strategies:
-The Heme Biosynthetic Pathway
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.
Porphobilinogen: < or =0.5 nmol/mL
Aminolevulinic Acid: < or =0.5 nmol/mL
Interpretation
Provides information to assist in interpretation of the test results
Abnormal results are reported with a detailed interpretation that may include an overview of the results and their significance, a correlation to available clinical information provided with the specimen, differential diagnosis, recommendations for additional testing when indicated and available, and a phone number to reach one 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 testing must be performed to distinguish among the acute porphyrias.
The specimen should be collected prior to treatment as therapy may decrease the amount of porphobilinogen (PBG) and aminolevulinic acid.
Specimens should be protected from light and frozen immediately following collection. PBG is susceptible to degradation at high temperatures and on prolonged exposure to light.
Clinical Reference
Recommendations for in-depth reading of a clinical nature
1.Tortorelli S, White A, Raymond K: Disorders of porphyrin metabolism. In: Dietzen DJ, Bennett MJ, Wong ECC, Haymond S eds. Biochemical and Molecular Basis of Pediatric Disease. 5th ed. Academic Press; 2021:503-528
2. Anderson KE, Lobo R, Salazar D, et al. Biochemical diagnosis of acute hepatic porphyria: Updated expert recommendations for primary care physicians. Am J Med Sci. 2021;362(2):113-121. doi:10.1016/j.amjms.2021.03.004
Method Description
Describes how the test is performed and provides a method-specific reference
In a microcentrifuge tube, internal standard and plasma are combined, centrifuged, and then subjected to solid phase extraction (SPE). The SPE eluate is evaporated and the residue is then reconstituted and subjected to liquid chromatography tandem mass spectrometry analysis.(Unpublished Mayo method)
PDF Report
Indicates whether the report includes an additional document with charts, images or other enriched information
Day(s) Performed
Outlines the days the test is performed. This field reflects the day that the sample must be in the testing laboratory to begin the testing process and includes any specimen preparation and processing time before the test is performed. Some tests are listed as continuously performed, which means that assays are performed multiple times during the day.
Wednesday
Report Available
The interval of time (receipt of sample at Mayo Clinic Laboratories to results available) taking into account standard setup days and weekends. The first day is the time that it typically takes for a result to be available. The last day is the time it might take, accounting for any necessary repeated testing.
Specimen Retention Time
Outlines the length of time after testing that a specimen is kept in the laboratory before it is discarded
Performing Laboratory Location
Indicates the location of the laboratory that performs the test
Fees :
Several factors determine the fee charged to perform a test. Contact your U.S. or International Regional Manager for information about establishing a fee schedule or to learn more about resources to optimize test selection.
- Authorized users can sign in to Test Prices for detailed fee information.
- Clients without access to Test Prices can contact Customer Service 24 hours a day, seven days a week.
- Prospective clients should contact their account representative. For assistance, contact Customer Service.
Test Classification
Provides information regarding the medical device classification for laboratory test kits and reagents. Tests may be classified as cleared or approved by the US Food and Drug Administration (FDA) and used per manufacturer instructions, or as products that do not undergo full FDA review and approval, and are then labeled as an Analyte Specific Reagent (ASR) product.
This test was developed and its performance characteristics determined by Mayo Clinic in a manner consistent with CLIA requirements. It has not been cleared or approved by the US Food and Drug Administration.
CPT Code Information
Provides guidance in determining the appropriate Current Procedural Terminology (CPT) code(s) information for each test or profile. The listed CPT codes reflect Mayo Clinic Laboratories interpretation of CPT coding requirements. It is the responsibility of each laboratory to determine correct CPT codes to use for billing.
CPT codes are provided by the performing laboratory.
CPT codes are provided by the performing laboratory.
82542
82135
LOINC® Information
Provides guidance in determining the Logical Observation Identifiers Names and Codes (LOINC) values for the order and results codes of this test. LOINC values are provided by the performing laboratory.
| Test Id | Test Order Name | Order LOINC Value |
|---|---|---|
| PBALP | PBG and ALA, P | 96911-3 |
| Result Id | Test Result Name |
Result LOINC Value
Applies only to results expressed in units of measure originally reported by the performing laboratory. These values do not apply to results that are converted to other units of measure.
|
|---|---|---|
| 38029 | Porphobilinogen, P | 17474-8 |
| 38028 | Aminolevulinic Acid, P | 79646-6 |
| 38030 | Interpretation (PBALP) | 59462-2 |
| 38031 | Reviewed By | 18771-6 |