Intravenous fluorescein interference with clinical laboratory tests.

Area of Science:

• Clinical Chemistry
• Diagnostic Imaging
• Pharmacology

Background:

• Fluorescein angiography is a common diagnostic procedure.
• Intravenous fluorescein administration may potentially affect subsequent laboratory test results.
• Understanding these interferences is crucial for accurate patient diagnosis.

Purpose of the Study:

• To investigate the interference of intravenous fluorescein on common clinical chemistry laboratory tests.
• To determine the duration of this interference after fluorescein injection.
• To identify specific analytes affected by fluorescein in serum and urine.

Main Methods:

• Four adult subjects received intravenous fluorescein.
• Serum and urine samples were collected at 5 minutes, 3, 6, and 12 hours post-injection.
• A panel of common serum and urine chemistry tests were performed on seven different instruments.
• Significant changes were defined as results exceeding +/- 3 coefficients of variation from baseline.

Main Results:

• Intravenous fluorescein significantly affected serum determinations of creatinine, total protein, cortisol, digoxin, quinidine, and thyroxine.
• No significant interference was observed in urine chemistry tests.
• The interference varied depending on the analyte and the time elapsed since fluorescein injection.

Conclusions:

• Physicians must be aware of potential interferences when interpreting clinical chemistry results following fluorescein angiography.
• Specific serum analytes are susceptible to falsely altered results due to fluorescein.
• Urine test results appear unaffected, providing a reliable alternative for monitoring.