Assessing toxicity
This test is not useful for assessing low-dose aspirin therapy
Photometric
ASA (Aspirin)
Aspirin (Acetylsalicylate)
Excedrin (Acetaminophen)
Salicylic Acid
Serum
Container/Tube:
Preferred: Serum gel
Acceptable: Red top
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 aliquoted within 2 hours of collection.
0.25 mL
Gross hemolysis | Reject |
Specimen Type | Temperature | Time | Special Container |
---|---|---|---|
Serum | Refrigerated (preferred) | 7 days | |
Frozen | 28 days | ||
Ambient | 72 hours |
Assessing toxicity
This test is not useful for assessing low-dose aspirin therapy
Therapeutic salicylates include, among others, salicylic acid, sodium salicylate, methyl salicylate (oil of wintergreen), and acetylsalicylic acid (aspirin).
Aspirin is an analgesic, antipyretic, anti-inflammatory drug contained in a large number of preparations. Aspirin is rapidly hydrolyzed by hepatic and blood esterases to the pharmacologically active intermediate, salicylic acid, which has a dose-dependent serum half-life ranging from 3 to 20 hours.
Stimulation of the respiratory center in the central nervous system and uncoupling of oxidative phosphorylation are direct effects of salicylate that lead to many of the toxic symptoms observed in overdose situations.
Symptoms of salicylate toxicity can include nausea, vomiting, tinnitus, headache, hyperpnea, confusion, hyperthermia, slurred speech, and convulsions. Acid-base disturbances such as compensated respiratory alkalosis (mild toxicity) and metabolic acidosis with increased anion gap (severe toxicity) are commonplace.
Therapeutic: <30.0 mg/dL
Critical value: > or =50.0 mg/dL
Therapeutic concentrations for antipyretic/analgesic are 3.0 to 10.0 mg/dL, while concentrations between 1.5 and 30 mg/dL are for anti-inflammatory effect and treatment of rheumatic fever.
Toxic concentrations are 50.0 mg/dL or higher.
This test is not intended for use with low-dose aspirin therapy. Most patients on low daily doses of aspirin for cardiovascular prophylaxis will have serum concentrations near or below the lower limit of the analytical range.
1. Done AK: Aspirin overdosage: incidence, diagnosis, and management. Pediatrics 1978;62:890-897
2. Medical Toxicology, Third edition, Edited by RC Dart. 2004 pp 1811
This determination depends upon the conversion of salicylate in the presence of the reduced form of nicotinamide adenine dinucleotide (NADH) by salicylate hydroxylase to catechol and nicotinamide adenine dinucleotide (NAD). The concomitant conversion of NADH to NAD is measured by the decrease in absorbance at 340 nm. The decrease is proportional to the concentration of salicylate present in the sample.(Package insert: Roche SALI reagent, Roche Diagnostics Corp, Indianapolis, IN)
Monday through Sunday
This test has been cleared, approved, or is exempt by the US Food and Drug Administration and is used per manufacturer's instructions. Performance characteristics were verified by Mayo Clinic in a manner consistent with CLIA requirements.
80179
Test Id | Test Order Name | Order LOINC Value |
---|---|---|
SALCA | Salicylate, S | 4024-6 |
Result Id | Test Result Name |
Result LOINC Value
Applies only to results expressed in units of measure originally reported by the performing laboratory. These values do not apply to results that are converted to other units of measure.
|
---|---|---|
SALCA | Salicylate, S | 4024-6 |