Test

Analytic Method

Advantages of Method

Disadvantages of Method

Detectable drugs

Relative cost

Color (spot)

Test

Sample response to color reagents

Simple. Immediate results can be read by eye.

Poor specificity (many false positives) Poor sensitivity (misses many true positives).

Most types

Cheap

*TLC

Interpretation of migratory pattern and colors of treated sample.

Adulteration of sample not possible.

Requires sample preparation. Hard copy of results difficult to obtain. Poor specificity (many false positives).

Most types** except cannabinoids, PCP and hallucinogens

Moderate

RIA

Radioactively labeled sample is compared as an antigen with non-labeled drug.

Give quantitative result.

Only one drug can be tested for at a time. Sensitive to tampered sample (produces false negatives). Drugs cross-react (produce false positives and false negatives).

Opiates, barbiturates amphetamines, cocaine, PCP, cannabis and LSD.

Equipment cost is high.

*EMIT

Non-radioactive comparison of enzyme activity.

Rapid. semi-quantitative negatives). May crossreact with some drugs.

Sensitive to tampered sample (produces false amphetamines, cocaine, PCP, cannabis, benzodiazepine, methaqualone and methadone.

Opiates, barbiturates, are costly.

Equipment cost is low. Reagents

FPIA

Measures fluorescence pattern of treated sample.

Rapid. Easy to do. Quantitative results. Highly sensitive.

Sensitive to tampered sample.

Expensive.