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Subject: An Evaluation of Non-Instrumented Drug Test Devices

Date: January 29, 1999

The Department of Health and Human Services (HHS) published in the Federal Register on April 11, 1988, the Mandatory Guidelines for Federal Workplace Drug Testing Programs. The Mandatory Guidelines detail comprehensive standards for laboratory procedures, specified drugs for which Federal employees can be tested, and established appropriate standards and procedures for periodic review of laboratories and criteria for certification of laboratories engaged in urine drug testing for Federal agencies. The Mandatory Guidelines were revised on June 9, 1994, but the basic requirement for laboratory testing was not changed. In addition to covering the testing of Federal employees in the Executive Branch of the Federal government, the Department of Transportation requires its regulated industries to use HHS certified laboratories.

During the past few years, there has been a rapid expansion in the private sector to test for the presence of illicit drugs in other biological specimens (such as, sweat, oral fluid, and hair) as well as the use of on-site urine drug test devices. Approximately 2 years ago, the Division of Workplace Programs (DWP) began a review of the testing of alternative specimens and the use of on-site test devices. As part of the review, DWP funded Duo Research, Incorporated, to conduct a study to evaluate the performance of on-site drug test devices currently being marketed. This study was actually a second study of 15 new or modified on-site test devices that had been originally evaluated for the Administrative Office of the U.S. Courts in 1996. As in the first study, this study focused on the testing of specimens clustered above and below the cutoffs, specimens that were clearly negative or positive, and known quality control samples.

This study is not intended to make recommendations for specific products, but to provide a general assessment of the performance of currently available non-instrumented drug test devices.

All known non-instrumented drug test manufacturers and device distributors were contacted to obtain devices. Of these, 15 devices were provided by the manufacturers or distributors. A Behring Diagnostics’ ETS instrument using Emit d.a.u. reagents served as a reference device. Other available instrumented systems were not included in the study.

The study was designed to test each device with 90 selected clinical specimens and 10 control samples for each drug. The specimens were selected from routine specimens submitted by Federal Probation Offices to PharmChem Laboratories under its contract with the Administrative Office of the U.S. Courts. They had been tested on an Hitachi 747 analyzer using Diagnostic Reagents, Inc (DRI) enzyme immunoassay test kits. The immunoassay rate data were compared to spiked control values to classify specimens into four categories: negative, below cutoff (ranging from about 25% below cutoff to cutoff), above cutoff (ranging from cutoff to about 25% above the cutoff), and high (greater than 25% above the cutoff). Approximately 60 specimens had responses in the below and above cutoff categories. Specimens testing negative were selected and stored frozen until needed. Positive specimens were selected from previously confirmed positives that were ready for disposal. For phencyclidine, a sufficient number of unique clinical specimens in the desired range was not available, so dilutions (with negative urine) of positive clinical specimens were performed. The accuracy of these dilutions was checked on the ETS prior to inclusion in the study and by gas chromatography/mass spectrometry (GC/MS) following the study.

Each day, 20 to 30 specimens for a given drug were thawed and tested on all the study devices. Specimens were identified to the operators only by bar coding. All devices in this study indicate a negative result by the appearance of a colored line at the area designated for each drug. Positive results are indicated by the absence of a line.

The performance of the devices was assessed in terms of their "Positive Predictive Values" (PPV) and "Negative Predictive Values" (NPV) and percentages of false positive and false negative results. These are standard analytical measures of the certainty of obtaining a correct positive and negative result, respectively. Thus, a high percentage or high PPV indicates that there is a high certainty that a positive result from the device will be confirmed as positive, or as negative for a high NPV.

This differs from the percentage of true positives, called sensitivity, and percentage of true negatives, called specificity. These measures indicate the percentage of all specimens confirmed positive by GC/MS that were identified as positive by the device, or of those confirmed as negative by GC/MS that were negative by the device. Also, specimens confirmed as positive but identified as negative by the device are false negative results, and for specimens confirmed as negative but identified as positive by the device are false positive results. The combination of all correct negative and positive results represents an estimate of the overall accuracy for both positive and negative results for each device.

The definitions used for this study are given below. Tables 1 through 5 show the PPV, NPV, and accuracy data for each test device versus GC/MS at the HHS cutoffs and with all borderline readings scored as negative (many devices give equivocal results, which were scored initially as "borderline") for each drug. Table 6 gives the combined results for all drugs for each test device. Figures 1 through 5 are the bar-graphs showing the sensitivity, false negatives, false positives, and specificity as percentages for each drug class for each test device ("PD" is used to represent the performance of a "Perfect Device"). Figure 6 gives the combined results for all drugs for each test device. It must be noted that the results for opiates were based on the 300 ng/mL cutoffs. None of the specimens included in the study would have been positive at 2,000 ng/mL.

Note: Codes have been used in the tables and figures contained in this report to conceal the identities of the test devices. However, each manufacturer has received a report that identifies the results for its test device.

The evaluation of the 15 devices was conducted with a majority of the specimens grouped around the screening cutoffs. It was found, as expected, that many devices gave a fair number of false positive and false negative results. It is also expected, based on experiences in the field, that specimens encountered in most workplace testing situations will have fewer specimens with drug concentrations near the cutoff. This means that a much higher percentage of confirmed positive results and fewer false negative results should occur during actual testing in the field.

The favorable performance of the devices was encouraging considering the simplicity of their design and operational requirements. Some devices were able to identify more positive specimens, but this was accompanied by a higher percentage of false positive results. Other devices were more conservative, giving few false positive results but missing many true positives.

Dipro 10 Panel

Each device is packaged in a sealed pouch. The device consists of a flat plastic card that has five dipsticks extending from one edge. Two of these are connected back-to-back providing for ten separate test strips. The strips are covered with a protective cap. Storage does not require refrigeration, but 36° to 86°F is recommended. Expiration dates are stamped on the pouches. The devices are well labeled, with clear result designations and areas for donor ID and date. The device includes a "control" or validity check. The test requires the removal of the cap, insertion of the dipsticks into the specimen for about 10 seconds. The cap can be replaced. The endpoint for a positive results if the absence of a line at the test band windows. Manufactured by American Biomedical, Inc.

Drug Check Cup

Each device is packaged in a sealed bag. Expiration dates are stamped on the bags. The devices are well labeled, with clear result designations. The device includes a "control" or validity check. The device is a self-contained collection and storage cup, that has the drug test strips imbedded in its side. The cup is closed with a screw-cap lid after specimen collection. The test begins as soon as the urine is added to the cup. There is no other activation step required. Results can be read within 5 to 9 minutes. The endpoint for a positive result is the absence of a line at the test band.

Dtx 520

Each cassette-style device is packaged in a sealed pouch with an attached pipette. Storage does not require refrigeration, but 36° to 86°F is recommended. Expiration dates are stamped on the pouches. The devices are well labeled, with clear result designations. The device includes a "control" or validity check. The test requires the addition of 4 to 5 drops of urine to a well at one end of the device. Results can be read within 3 to 8 minutes, but should be read within 8 minutes. The endpoint for a positive results is the absence of a line at the test band. Manufactured by Forefront Diagnostics, Inc.

Genie Cup

Each device is packaged in a sealed bag. Expiration dates are stamped on the bags. The devices are well labeled, with clear result designations. The device includes a "control" or validity check. The device is a self-contained collection and storage cup, that has the drug test strips imbedded in its side. The cup is closed with a screw-cap lid after specimen collection. At the time of testing, the lid is turned to its fully closed position. This depresses a plunger to trap a portion of the specimen in the test chamber. Results can be read as soon as a line appears in the "test valid" area. The endpoint for a positive result is the absence of a line at the test band. Timing is said not to be important. Manufactured by American Biomedical, Inc.

InstaCheck

Each cassette-style device is packaged in a sealed pouch with an attached pipette. Storage does not require refrigeration, but 36° to 86°F is recommended. Expiration dates are stamped on the pouches. The devices are well labeled, with clear result designations. The device includes a "control" or validity check. The test requires the addition of 4 to 5 drops of urine to a well at one end of the device. Results can be read within 3 to 8 minutes, but should be read within 8 minutes. The endpoint for a positive result is the absence of a line at the test band. Manufactured by Forefront Diagnostics, Inc.

PharmScreen Drug Screen Card

Each device is packaged in a sealed pouch. The device consists of a flat card that has five dipsticks extending from one edge. The strips are covered with a protective cap. Storage does not require refrigeration, but 36° to 86°F is recommended. Expiration dates are stamped on the pouches. The devices are well labeled, with clear designations and areas for donor ID and date. The device includes a "control" or validity check. The test requires the removal of the cap, insertion of the dipsticks into the specimen for about 10 seconds. The cap can be replaced. The endpoint for a positive result is the absence of a line at the test band windows. Manufactured by American Biomedical, Inc.

PharmScreen Drug Screen Multi

Each cassette-style device is packaged in a sealed pouch. Storage does not require refrigeration, but 36° to 86°F is recommended. Expiration dates are stamped on the pouches. The devices are well labeled, with clear result designations and areas for donor ID and date. The device includes a "control" or validity check. The test requires the addition of 4 to 5 drops of urine to a well at one end of the device. Results can be read within 3 to 8 minutes, but should be read within 8 minutes. The endpoint for a positive result is the absence of a line at the test band windows. Manufactured by American Biomedical, Inc.

Rapid Drug Screen

The device is a cup and a separate card containing the individual test strips. It is packaged in a sealed pouch. Expiration dates are stamped on the pouches. The devices are well labeled, with clear result designations and areas for donor ID and date. The device includes a "control" or validity check. The test requires the insertion of the test card through a slit in the lid and into the specimen. Results can be read within 3 minutes, but should be read within 8 minutes. The endpoint for a positive result is the absence of a line at the test band windows. Manufactured by American Bio Medica Corporation.

Status DS-5

Each cassette-style device is packaged in a sealed pouch with an attached pipette. Storage does not require refrigeration, but 35° to 86°F is recommended. Expiration dates are stamped on the pouches. The devices are well labeled, with clear result designations. The device includes a "control" or validity check. The test requires the addition of 3 drops of urine to a well at one end of the device. Results can be read within 3 to 5 minutes, but should be read within 10 minutes. The endpoint for a positive result is the absence of a line at the test band. Manufactured by Princeton BioMeditech.

Syva Rapid Test

Each cassette-style device is packaged in a sealed pouch with an attached pipette. Storage does not require refrigeration, but 35° to 86°F is recommended. Expiration dates are stamped on the pouches. The devices are well labeled, with clear result designations. The device includes a "control" or validity check. The test requires the addition of 3 drops of urine to a well at one end of the device. Results can be read within 3 to 5 minutes, but should be read within 10 minutes. The endpoint for a positive result is the absence of a line at the test band. Manufactured by Princeton BioMeditech.

TesTcup 5

Each device is packaged in a sealed bag. Storage does not require refrigeration, but 65° to 85°F is recommended. Expiration dates are stamped on the bags. The devices are well labeled, with clear result designations. The device includes a "control" or validity check. The device is a self-contained collection and storage cup, that has the drug test strips imbedded in its side. The cup is closed with a screw-cap lid after specimen collection. At the time of testing, the lid is turned to its "test"position, the cup tilted until the urine covers 1/2 to 3/4 of the lid (do not invert fully). It is held in this position for 10 seconds, then returned to its upright position. Results can be read as soon as the "TEST VALID" window develops a blue color, usually within 5 minutes. The endpoint for a positive result is the absence of a line at the test band. Timing is said not to be important. An adhesive covering strip is removed from the test display windows and placed on a small "breather" hole on the back of the cup. The lid should then be returned to the sealed position if the specimen is to be stored or sent for confirmation. Manufactured by Roche Diagnostic Systems, Inc.

Accutest

Each cassette-style device is packaged in a sealed pouch with an attached pipette. Storage does not required refrigeration, but 36° to 86°F is recommended. Expiration dates are stamped on the pouches. The devices are well labeled, with clear result designations. The device includes a "control" or validity check. The test requires the addition of urine from a pipette marked for about 0.2 mL to a well at one end of the device. Results can be read within 3 to 8 minutes, but should be read within 8 minutes. Manufactured by Jant Pharmacal Corporation.

One Step

Each device is packaged in a sealed pouch with an attached pipette. Storage does not require refrigeration, but can be if desired, or a room temperature, 65° to 85°F. Expiration dates are stamped on the pouches. The devices are well labeled. The device includes a "control" or validity check. The test is in the form of a dipstick, requiring the dipping of the strip into the urine, preferably a small aliquot in a test tube. Results can be read within 3 minutes, but must be read within 5 minutes. The endpoint for a positive result is the absence of a line at the test band. Manufactured by Technical Chemicals & Products, Inc.

QuickScreen

Each cassette-style device is packaged in a sealed pouch with an attached pipette. Storage does not required refrigeration, but 40° to 86°F is recommended. Expiration dates are stamped on the pouches. The devices are well labeled. The device includes a "control" or validity check. The test requires the slow addition of 4 drops of urine to a well at one end of the device. Results can be read within 10 minutes. The endpoint for a positive result is the absence of a line at the test band. Manufactured by PhamaTech.

TesTstik

Each device is packaged in a sealed pouch with an attached pipette. Storage does not require refrigeration, but 36° to 86°F is recommended. Expiration dates are stamped on the pouches. The devices are well labeled. The device includes a "control" or validity check. The test requires the dipping of the device into a urine samples up to a mark on the device for 5 to 7 seconds. Results can be read within 5 minutes, but should not be read after 30 minutes. The endpoint for a positive results is the absence of a line at the test band. Manufactured by Roche Diagnostic Systems, Inc.

True Positive (TP)

False Negative (FN)

False Positive (FP)

True Negative (TN)

Sensitivity

Specificity

Prevalence

Positive Predictive Value (PPV)

Negative Predictive Value (NPV)

Note: "a" is amphetamine specific, "m" is methamphetamine specific, "am" is sensitive to both amphetamines

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