Point of care (POC) drug testing is performed outside of the clinical laboratory in a location where the patient is receiving care.
The principle of POC drug testing devices is based on binding dye-conjugated antibodies to the drug in the patient's urine sample. POC immunoassay devices typically use dye-conjugated antibodies to bind specific drugs in the sample. The antibodies then laterally flow via capillary action. When the drug is present, the drug-antibody complexes are captured on a membrane that has a secondary antibody to the drug. The dyed detection antibodies congregate if the drug is present, and a colored line appears in the test window. POC tests can also use pre-labeled drugs as a reagent, which is then displaced by any drug present in the patient sample. This would be a competitive-type immunoassay test. Several POC test method variations can be utilized; check the package insert for your lab's test to see which test principle is employed.
Despite the obvious advantage of rapid results, there are disadvantages to POC testing compared to laboratory-based immunoassays. POC testing is typically performed by non-laboratory personnel and is more subjective. The tests are usually less precise than those of more automated and calibrated chemistry analyzers. Physicians should carefully evaluate the accuracy and value of POC devices before adopting them for routine use.
