Wallach's Interpretation of Diagnostic Tests: Pathways to Arriving at a Clinical Diagnosis (1197 page)

   ASA also inhibits platelet aggregation and, therefore, prolongs bleeding time.

   Interpretation

   See discussion of salicylate poisoning in Chapter
14
.

   Limitations

   Requires specific test request; not usually detected in routine screens:

   Color test:

   Limit of detection: 40–50 μg/mL

   Suitable for blood, serum, plasma, urine

   Not recommended for quantitative purposes due to interferences from metabolites, AND plasma constituents

   Immunoassay

   Serum/plasma.

   With a Limit of quantitation: 50 μg/mL.

   Not whole blood.

   Anticoagulants (heparin, citrates, oxalates, EDTA) do not interfere.