Blood Sciences Test


Drugs of abuse in urine

Please note, as from 05/2017 we are using new methodology to analyse drugs of abuse in urine.

These are screening tests with limitations of sensitivity and specificity (potential false negatives and positives respectively) and are NOT intended for medico-legal use. A positive result is reported if the concentration exceeds the clinical thresholds as defined by the national external quality assurance programme for drugs of abuse, which are far less stringent than workplace standards (see table below).

The sample should have a creatinine concentration of greater than 2 mmol/L to qualify as urine.

Methadone metabolites are NOT detectable by this method.

Specimen

Random urine

Intentional contamination with soap, salt, vinegar, etc. will interfere with the assay, and dilution with water will tend to produce negative results.

Special Instructions

The standard panel includes:

Cannabinoids is available as a separate test – please request this separately if this is required. Only one sample is required for both the standard panel and cannabinoids.  Please indicate which tests are required on the request form

Reference Range

SENSITIVITIES OF URINE SCREENING AND CONFIRMATION TESTS FOR DRUGS OF ABUSE

At concentrations below the limit of detection, the drug (or metabolite) will not normally be detected by the usual screening procedure.

A result reported as ‘positive’ in a screening test implies that the concentration of drug present is in excess of the limit given here.

Note that the sensitivity of drug detection will be reduced in dilute urine specimens.

DRUG CLASS LIMIT OF DETECTION OF SCREENING TEST CLINICAL THRESHOLD
Amphetamines 1000 µg/L 1000 ug/L
Benzodiazepines 300 µg/L 300 ug/L
Cannabinoids 50 µg/L 65 ug/L
Cocaine (metabolite) 300 µg/L 300 ug/L
Codeine 300 µg/L
Methadone 300 µg/L 500 ug/L
Morphine 300 µg/L 1000 ug/L

The duty biochemist may be contacted if you have a query relating to cross reactivity of other drugs in the assay. ext 2935

Units

None. Results reported as “Positive” or “Negative”

Test Usage

Abuse and Compliance (methadone)

Turnaround Time

4 days (urgent requests can be processed the same day following contact with the laboratory)

Availability

Local test

Can be added on to an existing request up to 4 days following sample receipt

Accreditation

Please note this test is not UKAS accredited

Specimen Labelling Procedure