Caffeine, Serum or Plasma

CPT: 80155
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Test Details

Synonyms

  • Cafcit®
  • Energets
  • No Doz® Maximum Strength
  • Vivarin®

Use

Monitor caffeine concentration in newborns receiving theophylline or caffeine.

Half-life elimination: Neonates 72 to 96 hours, Children >9 months and Adults: 5 hours

Time to peak serum, oral: Within 30 minutes to 2 hours

Methodology

Liquid chromatography/tandem mass spectrometry (LC/MS-MS)

Reference Interval

Therapeutic: 3.0−15.0 μg/mL

• Neonatal apnea: 8−14 μg/mL

• Infant (<1 year): 8−20 μg/mL

Critical Value

Potentially toxic: >50.0 μg/mL

Additional Information

Theophylline is used to treat neonatal apnea. Unlike its metabolism in adults, theophylline in neonates is extensively metabolized to caffeine. Plasma elimination half-life in adults is three to six hours. In neonates, caffeine has a half-life of 30 hours. Caffeine overdoses are rare. The clinical presentation is similar to that of theophylline.

Specimen Requirements

Specimen

Serum or plasma

Volume

1 mL

Minimum Volume

0.3 mL

Container

Red-top tube, lavender-top (EDTA) tube, or green-top (heparin) tube. Do not use a gel-barrier tube. The use of gel-barrier tubes is not recommended due to slow absorption of the drug by the gel. Depending on the specimen volume and storage time, the decrease in drug level due to absorption may be clinically significant.

Collection

Transfer separated serum or plasma to a plastic transport tube.

Storage Instructions

Room temperature

Stability Requirements

Temperature

Period

Room temperature

14 days

Refrigerated

14 days

Frozen

14 days

Freeze/thaw cycles

Stable x3

Causes for Rejection

Gel-barrier tube

Clinical Information

References

Drug Information Handbook. 24th ed. Hudson, OH: Wolters Kluwer Clinical Drug Information, Inc; 2015; 319-321.

LOINC® Map

Order Code Order Code Name Order Loinc Result Code Result Code Name UofM Result LOINC
071258 Caffeine, Serum 3422-3 071262 Caffeine, Serum ug/mL 3422-3
Reflex Table for Caffeine, Serum
Order Code Order Name Result Code Result Name UofM Result LOINC
Reflex 1 007000 See below: 007000 See below: N/A

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