Salicylate, plasma or serum

Alternate test name

ASA, Aspirin

Lab area

Clinical Biochemistry - General

Method and equipment

Equipment : Roche Cobas Pro c503

Method : This determination depends upon the conversion of salicylate in the presence of NADH by salicylate hydroxylase to catechol and 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.

Expected turn-around time

STAT/ Urgent/ Routine: 2 hours

Specimen type

Serum, Plasma Lithium Heparin

Specimen requirements

150 uL

Storage and transportation

4°C (transport with a cool pack if possible)

Shipping information

The Hospital for Sick Children

Rapid Response Laboratory

555 University Avenue, Room 3642

Toronto, ON

Canada

M5G 1X8

Phone: 416-813-7200

Toll Free: 1-855-381-3212

Hours: 7 days/week, 24 hours/day

Requisition

Salicylate, plasma or serum - requisition

Background and clinical significance

Salicylates, sold as Aspirin or Acetylsalicyclic Acid (ASA), possess anti-inflammatroy, analgesic and antipyretic properties. They are available in many formulations including tablets, capsules, liquids and topical forms such as creams or lotions. Metabolism is primarily hepatic with renal elimination. In overdose situations a severe metabolic acidosis with a compensatory respiratory alkalosis may develop.

Central respiratory centre stimulation a hyperventilation a respiratory alkalosis Inhibition of Krebs Cycle enzymes & uncoupling of oxidative phosphorylation a metabolic acidosis which leads to a increase in glycolysis a hypoglycemia.

Alteration in capillary integrity a pulmonary and cerebral edema.

Alteration of platelet function and prolongation of prothrombin time Clinical symptoms of salicylate toxicity include: pulmonary, auditory (ototoxicity, tinnitus), cardiovascular (tachycardia, hypotension), neurologic (CNS depression, seizures), gastrointestinal (nausea, vomiting), genitourinary (renal failure), hematological and electrolyte disturbances (dehydration, hypokalemia, hypocalcemia & acidemia.