Procainamide, Serum or Plasma

Also known as: Pronestyl®

Clinical Use

Use

The test is used to monitor the levels of procainamide and its active metabolite N-acetyl procainamide (NAPA) in patients' blood. Procainamide is used in the treatment of various cardiac arrhythmias. Monitoring is essential as the drug exhibits significant interindividual variability in metabolism, especially influenced by genetic factors. Impaired renal function can significantly alter drug disposition, particularly for NAPA, and prolonged half-life can be observed in geriatric patients.

Special Instructions

Not provided.

Limitations

The rate of metabolism for procainamide is genetically determined, differentiating patients into slow and fast acetylator types. As such, the test cannot account for all variations due to genetic differences. Furthermore, patients with severe renal dysfunction may experience a prolonged and highly variable half-life of the drug, which the test cannot fully account for. Additionally, the use of gel-barrier tubes can result in incorrect measurement due to absorption, which represents another limitation of the testing process.

Test Details

Methodology

Immunoassay

Biomarkers

N-acetylprocainamide (NAPA)

Analyte

Concentration / Level

Concentration / Level • Quantitative (Continuous) (e.g., copies/mL, % expression)

Procainamide

Analyte

Concentration / Level

Concentration / Level • Quantitative (Continuous) (e.g., copies/mL, % expression)

LOINC Codes

Order Codes

88699-4 - Procainamide & NAPA panel SerPl

Result Codes

3982-6 - Procainamide SerPl-mCnc
3834-9 - NAPA SerPl-mCnc
3983-4 - Procainamide+NAPA SerPl-mCnc

Result Turnaround Time

1 day

Specimen

Serum

Volume

1 mL

Minimum Volume

0.3 mL

Container

Red-top tube or green-top (heparin) tube. Do not use a gel-barrier tube.

Collection Instructions

Transfer separated serum or plasma to a plastic transport tube. Oral treatment: peak: 75 minutes after dose; trough: immediately before next dose. I.V. treatment: immediately after loading dose; 2, 6, 12, and 24 hours after starting I.V. maintenance.