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23018 Thiamin, Vitamin B1, Whole Blood (TDP)

Thiamin, Vitamin B1, Whole Blood (TDP)
Test Code: THIASO
Synonyms/Keywords
​Ref Lab Code: 85753, B1, Vitamin, Thiamin Diphosphate (TDP), Thiamin Pyrophosphate (TPP),
Thiamine, Vitamin B1, VITB1
Useful For
Assessment of thiamin deficiency
 
Thiamin measurement 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​
Specimen Requirements
Fasting Required Specimen Type Preferred Container/Tube Acceptable Container/Tube Specimen Volume Specimen Minimum Volume
(allows for 1 repeat)
Pediatric Minimum Volume
(no repeat)
Yes​ ​Whole blood ​EDTA Lavender Top Tube (LTT) ​4 mL ​0.5 mL
Collection Processing Instructions
1. Fasting-overnight (12-14 hours) (infants-draw prior to next feeding). Water can be taken as needed.
2. Invert 8 to 10 times to mix blood.
3. Immediately place specimen on wet ice. Maintain specimen on wet ice and process within 4 hours of draw.
4. Transfer whole blood into amber vial to protect from light.
5. Freeze vial immediately.
Specimen Stability Information
Specimen Type Temperature Time
Whole Blood EDTA ​Frozen ​7 days
Rejection Criteria
Glass vial, clotted specimen, washed erythrocytes, anticoagulant other than EDTA, or non-light protected container
Performing Laboratory Information
Performing Location Day(s) Test Performed Analytical Time Methodology/Instrumentation
​Mayo Medical Laboratories Monday through Friday​ ​2 days (not reported on Saturday or Sunday)
High-Performance Liquid Chromatography (HPLC) with Fluorescence Detection​
Reference Lab
Test Information
Thiamin (vitamin B1) is an essential vitamin required for carbohydrate metabolism, brain function, and peripheral nerve myelination. Thiamin is obtained from the diet. Body stores are limited and deficiencies can develop quickly. The total thiamin pool in the average adult is about 30 mg. An intake of 0.5 mg per 1,000 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 thiamin deficient due to poor nutrition. However, deficiency also can occur in individuals who are elderly, have chronic gastrointestinal problems, have marked anorexia, are on cancer treatment, or are receiving diuretic therapy.
 
The signs and symptoms of mild-to-moderate thiamin deficiency are nonspecific and may include poor sleep, malaise, weight loss, irritability, and confusion. Newborns breast fed 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 thiamin 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 thiamin therapy in deficient patients is usually rapid. Thiamin deficiency is a treatable, yet under diagnosed, disorder in the United States. A heightened level of awareness of the possibility of thiamin deficiency is necessary to identify, intervene, and prevent thiamin deficiency's dire consequences. It appears that no conditions are directly attributable to thiamin excess and that thiamin administration is safe except in extremely rare cases of anaphylaxis from intravenous thiamin.
 
Whole blood thiamin testing is superior to currently available alternative tests for assessing thiamin status. Serum or plasma thiamin testing suffers from poor sensitivity and specificity, and <10% of blood thiamin is contained in plasma. Transketolase determination, once considered the most reliable means of assessing thiamin 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 HPLC, has poor precision, and specimen stability concerns.        
 
Thiamin diphosphate is the active form of thiamin and is most appropriately measured to assess thiamin status. Thiamin diphosphate in circulating blood is present in erythrocytes, but is undetectable (present in very low levels) in plasma or serum. HPLC analysis of thiamin diphosphate in whole blood or erythrocytes is the most sensitive, specific, and precise method for determining the nutritional status of thiamin and is a reliable indicator of total body stores. This assay specifically targets and quantitates the active form of vitamin B1 (thiamin diphosphate) as an indicator of vitamin B1 status.
Reference Range Information
Performing Location Reference Range
​Mayo Medical Laboratories ​70-180 nmol/L
Interpretation
Values for thiamin diphosphate <70 nmol/L are suggestive of thiamin deficiency. ​
Outreach CPTs
CPT Modifier
(if needed)
Quantity Description Comments
​84425
Synonyms/Keywords
​Ref Lab Code: 85753, B1, Vitamin, Thiamin Diphosphate (TDP), Thiamin Pyrophosphate (TPP),
Thiamine, Vitamin B1, VITB1
Ordering Applications
Ordering Application Description
If the ordering application you are looking for is not listed, contact your local laboratory for assistance.
Specimen Requirements
Fasting Required Specimen Type Preferred Container/Tube Acceptable Container/Tube Specimen Volume Specimen Minimum Volume
(allows for 1 repeat)
Pediatric Minimum Volume
(no repeat)
Yes​ ​Whole blood ​EDTA Lavender Top Tube (LTT) ​4 mL ​0.5 mL
Collection Processing
1. Fasting-overnight (12-14 hours) (infants-draw prior to next feeding). Water can be taken as needed.
2. Invert 8 to 10 times to mix blood.
3. Immediately place specimen on wet ice. Maintain specimen on wet ice and process within 4 hours of draw.
4. Transfer whole blood into amber vial to protect from light.
5. Freeze vial immediately.
Specimen Stability Information
Specimen Type Temperature Time
Whole Blood EDTA ​Frozen ​7 days
Rejection Criteria
Glass vial, clotted specimen, washed erythrocytes, anticoagulant other than EDTA, or non-light protected container
Useful For
Assessment of thiamin deficiency
 
Thiamin measurement 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​
Reference Range Information
Performing Location Reference Range
​Mayo Medical Laboratories ​70-180 nmol/L
Interpretation
Values for thiamin diphosphate <70 nmol/L are suggestive of thiamin deficiency. ​
For more information visit:
Performing Laboratory Information
Performing Location Day(s) Test Performed Analytical Time Methodology/Instrumentation
​Mayo Medical Laboratories Monday through Friday​ ​2 days (not reported on Saturday or Sunday)
High-Performance Liquid Chromatography (HPLC) with Fluorescence Detection​
Reference Lab
For billing questions, see Contacts
Outreach CPTs
CPT Modifier
(if needed)
Quantity Description Comments
​84425
For most current information refer to the Marshfield Laboratory online reference manual.