acetaminophen in serum/plasma
Indications
- evaluation of acetaminophen toxicity
Reference interval
- Male & Female: 10-200 ug/mL
Principle
The unique reagents in this methodology are the matched lots of acetaminophen antibody & acetaminophen-glucose-6-phosphate dehydrogenase conjugate. The reaction sequence, in two steps, is as shown:
ACTM Ab-ACTM
- Ab + + -------> + + ACTM-G6PD
ACTM-G6PD Ab-ACTM-G6PD (active)
(inhibited)
Glucose-6-phosphate ACTM-G6PD 6-Phosphogluconolactone
- + ---------------> +
NAD+ (active) NADH(absorbs at 340 nm)
Where: Ab = Acetaminophen Antibody
ACTM = Acetaminophen
ACTM-G6PD = Acetaminophen-glucose-6-phosphate dehydrogenase conjugate
The concentration of acetaminophen determines the amount of acetaminophen-glucose-6-phosphate dehydrogenase conjugate (ACTM- G6PD) that is bound to the anti-acetaminophen antibody. The unbound conjugate catalyzes the oxidation of glucose-6-phosphate with the simultaneous reduction of NAD+ to NADH more rapidly than does the bound conjugate. The rate of increasing absorbance at 340 nm due to the increase in NADH is related to acetaminophen concentration by means of a mathematical function
Clinical significance
Acetaminophen is a widely used analgesic that is available without prescription & is frequently recommended when aspirin may present problems to a patient, particularly in pediatrics or after surgery. It can produce liver toxicity when taken in overdose due to the conversion to a toxic metabolite. Normally, the metabolite is conjugated with glutathione & excreted. Analysis not only confirms a suspected overdosage but, by additional analysis of times specimens, can offer a means of estimating the half-life of the drug. A lengthened half-life of the drug indicates that liver toxicity may occur.
Specimen
Patient Preparation: No special patient preparation is required.
- Serum is the specimen of choice. Specimens are collected by venipuncture in a red top vacutainer. Specimen is stable for at least one week at room temperature & 1 year if frozen at -20C.
- Plasma samples are also acceptable. These samples are collected by venipuncture in a green top tube. Hemolysis, icterus, & lipemia do not interfere with the ACTM method.
Minimum sample size required is .5 milliliter: with an optimum size of 1.0 milliliters or larger.
More general terms
More specific terms
- acetaminophen free in serum/plasma
- acetaminophen+codeine in serum/plasma
- acetaminophen+oxycodone in serum/plasma
Additional terms
- acetaminophen (Tylenol, Paracematol, Panadol, Tempra, Datril, APAP, non-Aspirin)
- acetaminophen poisoning
References
- ↑ Kaplan, L., & Pesce, A., Clinical Chemistry:theory, analysis, & correlation, C. V. Mosby Co., St. Louis, MO., 1984, pp. 1330.
- ↑ Tietz, N., Fundamentals of Clinical Chemistry, 3rd edition W. B. Saunders Co., Philadelphia, 1987, pp. 899.
- ↑ Tietz, N., Textbook of Clinical Chemistry, W. B. Saunders Co., Philadelphia, 1986, pp. 1731-1732.
- ↑ ACA IV Discrete Clinical Analyzer Instrument Manual, Volume 1:Operation, DuPont Company, Wilmington, Delaware, 1984.
- ↑ ACA IV Discrete Clinical Analyzer Instrument Manual, Volume 3:Chemistry, DuPont Company, Wilmington, Delaware, 1984.
- ↑ Package Insert, DuPont ACTM Calibrators, DuPont Company, Medical Products, Wilmington, Delaware, 1989.
- ↑ Acetaminophen Laboratory Test Directory ARUP: http://www.aruplab.com/guides/ug/tests/0090001.jsp