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Order Code CAFF Caffeine, Serum


Specimen Required


Supplies: Sarstedt Aliquot Tube, 5 mL (T914)

Collection Container/Tube:

Preferred: Serum gel

Acceptable: Red top

Submission Container/Tube: Plastic vial

Specimen Volume: 0.5 mL

Collection Instructions:

1. Serum gel tubes should be centrifuged within 2 hours of collection.

2. Red-top tubes should be centrifuged and the serum aliquoted into a plastic vial within 2 hours of collection.


Useful For

Monitoring caffeine therapy in neonates

 

Assessing caffeine toxicity in neonates

Method Name

Enzyme Multiplied Immunoassay Technique (EMIT)

Reporting Name

Caffeine, S

Specimen Type

Serum

Specimen Minimum Volume

0.25 mL

Specimen Stability Information

Specimen Type Temperature Time Special Container
Serum Frozen (preferred) 28 days
  Ambient  72 hours
  Refrigerated  72 hours

Reject Due To

Gross hemolysis Reject

Reference Values

Therapeutic: 8.0-20.0 mcg/mL

Critical value: ≥30.0 mcg/mL

Method Description

The enzyme-multiplied immunoassay technique assay is a homogeneous enzyme immunoassay technique used for the analysis of specific compounds in biological fluids. The assay is based on competition between drug in the sample and drug labeled with the enzyme glucose-6-phosphate dehydrogenase (G6PD) for antibody binding sites. Enzyme activity decreases upon binding to the antibody, so the drug concentration in the sample can be measured in terms of enzyme activity. Active enzyme converts oxidized nicotinamide adenine dinucleotide (NAD) to NADH, resulting in an absorbance change that can be measured spectrophotometrically. Endogenous serum G6PD does not interfere because the coenzyme functions only with the bacterial (Leuconostoc mesenteroides) enzyme employed in the assay.(Package insert: Caffeine Reagent. Seimens Healthcare Diagnostics, Ltd; 03/2015)

Day(s) Performed

Monday through Saturday

Performing Laboratory

Mayo Clinic Laboratories in Rochester

CPT Code Information

80155

Forms

If not ordering electronically, complete, print, and send a Therapeutics Test Request (T831) with the specimen.