Test Catalog

Test Id : TDP

Thiamine (Vitamin B1), Whole Blood

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

Assessment of thiamine deficiency


Measuring thiamine levels in patients with behavioral changes, eye signs, gait disturbances, delirium, and encephalopathy; or in patients with questionable nutritional status, especially those who appear at risk and who also are being given insulin for hyperglycemia


-Whole blood thiamine testing is superior to currently available alternative tests for assessing thiamine status. Serum or plasma thiamine testing suffers from poor sensitivity and specificity, and less than 10% of blood thiamine is contained in plasma.


-Thiamine diphosphate (TDP) is the active form of thiamine and is most appropriately measured to assess thiamine status. Thiamine diphosphate in circulating blood is present in erythrocytes but is undetectable (present in very low levels) in plasma or serum.


-Liquid chromatography-tandem mass spectrometry analysis of TDP in whole blood is the most sensitive, specific, and precise method for determining the nutritional status of thiamine and is a reliable indicator of total body stores.


-This assay specifically targets and quantitates the active form of thiamine, TDP, as an indicator of thiamine status.

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

Thiamin (Vitamin B1), WB

Lists additional common names for a test, as an aid in searching

Thiamin Diphosphate (TDP)

Thiamin Pyrophosphate (TPP)


Vitamin B1


B1, Vitamin

Specimen Type
Describes the specimen type validated for testing

Whole Blood EDTA

Shipping Instructions

Specimen Required
Defines the optimal specimen required to perform the test and the preferred volume to complete testing

Patient Preparation: Fasting overnight (12-14 hours). Infants-collect prior to next feeding. Water can be taken as needed.

Supplies: Sarstedt 5 mL Aliquot Tube (Amber) (T915)

Collection Container/Tube: Lavender top (EDTA)

Submission Container/Tube: Amber vial

Specimen Volume: 4 mL

Collection Instructions:

1. Invert 8 to 10 times to mix blood.

2. Transfer whole blood into amber vial or tube and freeze within 24 hours of collection.


If not ordering electronically, complete, print, and send a General Request (T239) with the specimen.

Specimen Minimum Volume
Defines the amount of sample necessary to provide a clinically relevant result as determined by the Testing Laboratory

0.5 mL

Reject Due To
Identifies specimen types and conditions that may cause the specimen to be rejected

Gross lipemia Reject
Glass vial
Clotted specimen

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
Whole Blood EDTA Frozen 28 days LIGHT PROTECTED

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

Assessment of thiamine deficiency


Measuring thiamine levels in patients with behavioral changes, eye signs, gait disturbances, delirium, and encephalopathy; or in patients with questionable nutritional status, especially those who appear at risk and who also are being given insulin for hyperglycemia

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

Thiamine (vitamin B1, thiamin) is an essential vitamin required for carbohydrate metabolism, brain function, and peripheral nerve myelination. Thiamine is obtained from the diet. Body stores are limited, and deficiencies can develop quickly. The total thiamine pool in the average adult is about 30 mg. An intake of 0.5 mg per 1000 kcal per day is needed to maintain this pool. Due to its relatively short storage time, marginal deficiency can occur within 10 days and more severe deficiency within 21 days if intake is restricted.


Approximately 80% of all chronic alcoholics are thiamine deficient due to poor nutrition. However, deficiency also can occur in individuals who are older adults, have chronic gastrointestinal problems, have marked anorexia, are on cancer treatment, or are receiving diuretic therapy.


The signs and symptoms of mild-to-moderate thiamine deficiency are nonspecific and may include poor sleep, malaise, weight loss, irritability, and confusion. Newborns breastfed from deficient mothers may develop dyspnea and cyanosis; diarrhea, vomiting, and aphonia may follow. Moderate deficiency can affect intellectual performance and well-being, despite a lack of apparent clinical symptoms.


Severe deficiency causes congestive heart failure (wet beriberi), peripheral neuropathy (dry beriberi), Wernicke encephalopathy (a medical emergency that can progress to coma and death), and Korsakoff syndrome (an often irreversible memory loss and dementia that can follow). Rapid treatment of Wernicke encephalopathy with thiamine can prevent Korsakoff syndrome. Symptoms of dry beriberi include poor appetite, fatigue, and peripheral neuritis. Symptoms of wet beriberi include cardiac failure and edema. Patients with Wernicke encephalopathy present with behavior change (confusion, delirium, apathy), diplopia (often sixth nerve palsies), and ataxia. A late stage, in which the patients may develop an irreversible amnestic confabulatory state, is referred to as the Wernicke-Korsakoff syndrome.


The response to thiamine therapy in deficient patients is usually rapid. Thiamine deficiency is a treatable, yet underdiagnosed, disorder in the United States. A heightened level of awareness of the possibility of thiamine deficiency is necessary to identify, intervene, and prevent thiamine deficiency's dire consequences. It appears that no conditions are directly attributable to thiamine excess and that thiamine administration is safe except in extremely rare cases of anaphylaxis from intravenous thiamin.


Whole blood thiamine testing is superior to currently available alternative tests for assessing thiamine status. Serum or plasma thiamine testing suffers from poor sensitivity and specificity, and less than 10% of blood thiamine is contained in plasma. Transketolase determination, once considered the most reliable means of assessing thiamine status, is now considered an inadequate method. The transketolase method is an indirect assessment. Since transketolase activity requires thiamin, decreased transketolase activity is presumed to be due to the decrease of thiamin. However, the test is somewhat nonspecific, as other factors may decrease transketolase activity. Transketolase is less sensitive than liquid chromatography-tandem mass spectrometry), has poor precision, and specimen stability concerns.

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.

70-180 nmol/L

Provides information to assist in interpretation of the test results

Values for thiamine diphosphate of less than 70 nmol/L are suggestive of thiamine deficiency.

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

Vitamin supplementation and nonfasting specimens may result in elevated thiamine diphosphate concentrations.

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

1. Naidoo DP, Bramdev A, Cooper K: Wernicke's encephalopathy and alcohol-related disease. Postgrad Med J. 1991 Nov;67(793);978-981

2. Herve C, Beyne P, Letteron PH, Delacoux E: Comparison of erythrocyte transketolase activity with thiamin and thiamin phosphate ester levels in chronic alcoholic patients. Clin Chim Acta. 1995 Jan;234(1-2):91-100

3. Majumdar SK, Shaw GK, O'Gorman P, et al: Blood vitamin status (B1, B2, B6, folic acid, and B12) in patients with alcohol liver disease. Int J Vitam Nutr Res. 1982;52:266-271

4. Ball GFM: Vitamins: Their role in the human body. Blackwell Publishing; 2004:273-288

5. Brin M: Erythrocyte as a biopsy tissue for functional evaluation of thiamin adequacy. JAMA. 1964 Mar;187:762-766

6. Roberts NB, Taylor A. Sodi R: Vitamins and trace elements. In: Rifai N, Horwath AR, Wittwer CT, eds. Tietz Textbook of Clinical Chemistry and Molecular Diagnostics. 6th ed. Elsevier; 2018:639-718

Method Description
Describes how the test is performed and provides a method-specific reference

Samples are extracted with methanol and an isotopically labeled internal standard. Following centrifugation, an aliquot of the supernatant is dried down and reconstituted. The analyte is then detected using liquid chromatography-tandem mass spectrometry.(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.

Monday through Thursday

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.

3 to 6 days

Specimen Retention Time
Outlines the length of time after testing that a specimen is kept in the laboratory before it is discarded

14 days

Performing Laboratory Location
Indicates the location of the laboratory that performs the test


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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.


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
TDP Thiamin (Vitamin B1), WB 32554-8
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.
85753 Thiamin (Vitamin B1), WB 32554-8

Test Setup Resources

Setup Files
Test setup information contains test file definition details to support order and result interfacing between Mayo Clinic Laboratories and your Laboratory Information System.

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Sample Reports
Normal and Abnormal sample reports are provided as references for report appearance.

Normal Reports | Abnormal Reports

SI Sample Reports
International System (SI) of Unit reports are provided for a limited number of tests. These reports are intended for international account use and are only available through MayoLINK accounts that have been defined to receive them.

SI Normal Reports | SI Abnormal Reports