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Test Code FOLS Folate, Serum

Important Note

This test may be affected by biotin interference. Patients on high dose biotin (5mg/day or more) should not have samples drawn until at least 24 hours after the last biotin administration.

Specimen and Container/Tube

Specimen Type: Serum

Preferred Specimen: Red Top

Other Acceptable specimens: Serum/Gold Top

Specimen Handling and Transport Instructions

UCMC Onsite Instructions: 

Collect specimen per standard collection procedure and send to laboratory immediately. 

 

UCMC Offsite and UC MedLab Outreach Instructions: 

  • Samples should be centrifuged within 2 hours of collection.
  • Centrifuge specimens at >2500 x g for 10 minutes at room temperature.
  • Aliquot sample into plastic transport tube containing a minimum of 0.2 mL of specimen.
  • Samples must be sent refrigerated at 2-8oC.

 

Rejection Criteria

  • Common specimen rejected situations include: incorrect specimen type, insufficient volume, missing or incomplete specimen identifiers, incorrect specimen transport, or specimens outside stability limits. 
  • Specimens that are clotted or grossly hemolyzed.
  • Specimens that were transported unspun/whole blood and draw time is greater than 6 hours

Reference Values

 

Test

Age

Sex

Reference Range

FOLS

All

All

4.0 - 26.0 ng/mL

Note: Reference ranges are based on in-house studies performed at the University of Chicago Medicine per the Roche cobas 8000 modular anaylzer series e 801 System Installation Workbook and the Elecsys Folate III product insert.  

Critical Values

Analyte

Unit

Low

High

Age

N/A

N/A

N/A

N/A

N/A

CPT Codes

82746

LOINC Codes

2284-8

Volume

Preferred Volume: 0.5 mL

Minimum Volume: 0.2 mL

Specimen Stability

Storage Temperature

Stability

Room temperature

2 hours

Refrigerated

48 hours

Frozen

28 days

Collection Instructions

Collect specimen per standard laboratory collection procedures. 

 

Test Components

Folate

Clinical Indications

Useful in the evaluation of folate deficiency.

Methodology

Electrochemiluminescence immunoassay (ECLIA) - Roche Diagnostics

Additional Information

  • Results should always be assessed in conjunction with RBC folate, patient's medical history, clinical examination and other findings.
  • Folic acid measurments are used in the diagnosis and treatment of anemia.
  • Because vitamin B12 and folate are closely interrelated in the cellular one-carbon unit metabolism, and also hematologic and clinical consequences of the two vitamin deficiency states might be similar, it is advisable to determine both paramerters simultaneously in patients with the relevant symptoms of vitamin deficiency.
  • Hemolysis may significantly increase folate values due to high concentrations of folate in red blood cells. Therefore, hemolyzed samples are not suitable for use.
  • Samples for folate determinations should be collected from fasting persons.
  • Samples with extremely high total protein concentrations (hyerproteinemia) are not suitable for use in this assay.
  • It is contraindicated to measure samples of patients receiving therapy with certain pharmaceuticals, e.g. methotrexate or leucovorin, because of the cross-reactivity of folate binding protein with these compounds.
  • In rare cases, interference due to extremely high titers of antibodies to streptavidin and ruthenium can occur.

Turnaround Time

Turnaround times are relative to the time the specimen is received in the test laboratory. 

 

STAT Turnaround Time: Not Available as STAT test

Routine Turnaround Time: up to 4 hours

Testing Schedule:  24/7

Synonyms/Keyword Search

Folic Acid, Pteroyglutamic Acid

Last Review Date

1/26/23

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