Table of Contents

A. Need for a QA/QC Program
B. Selection and Validation

LMPG: Laboratory Support for Emergency Toxicology
 
(Draft Guidelines)

Part III. Recommendations for BREATH ALCOHOL ANALYSIS

A. Need for a QA/QC Program

Portable and bench-top breath alcohol devices have been available for many years and are widely used for traffic law enforcement.  Current alcohol breath analyzers are accurate, precise, and inexpensive.  As a result, many emergency departments have adopted breath meters for determining bedside alcohol concentrations in intoxicated patients.  Currently, the Health Care Finance Administration (HCFA) and the Clinical Laboratory Improvement Act 1988 (CLIA 88) does not regulate breath alcohol testing because a discrete sample is not collected and separately analyzed (the exhalation of breath directly into a device does not constitute a sample collection).  Thus in the manner that a pulse oximeter measurement is not subject to CLIA 88 regulations, neither is breath alcohol measurement.  Nevertheless, due to the importance of alcohol measurement, the Committee feels that laboratory oversight is necessary.  The recommendations that follow were formulated by a Task Force of the American Association for Clinical Chemistry, Therapeutic Drug Monitoring and Clinical Toxicology Division (39).

Recommendation: Clinical breath alcohol testing is point-of-care testing (POCT) and must meet the same quality assurance (QA)/quality control (QC) requirements as any POC test.  A quality assurance program must be in place to monitor and evaluate policy, protocols, and the total testing process so that breath alcohol results are accurate and reliable.  The clinical laboratory should be involved in the design, implementation, and monitoring of the quality assurance program.

Discussion

Elements of an effective QA program include monitoring and evaluating the overall quality of the total testing process (pre-analytic, analytic and post-analytic steps) as well as the evaluation of effectiveness of policies and procedures, identification and correction of problems, assurance of accurate, reliable, and prompt reporting of test results, and affirming the competency of operators.  It is necessary to have a comprehensive up-to-date accessible Standard Operating Procedure (SOP) manual, operator training and evaluation of competency, and a QC program.  Each device must be checked for accuracy each day by use of a dry gas standard and an air blank. The recover of alcohol must be within the tolerance established by the manufacturer.  The essential operator procedures are listed in Table 3.

Table 3.  Essential Operator Procedures for Breath Alcohol Analysis

  • Use of test device under manufacturer recommended environmental conditions

  • Use of a properly calibrated device

  • Verification that the blank and alcohol accuracy (QC) recoveries are within specifications

  • Use of an air check or blank breath test immediately prior to the patient test

  • Confirmation of patient identification

  • Observation of the patient to ascertain that residual alcohol and foreign objects are cleared from the mouth

  • Instruction of patient on proper delivery of a deep-lung sample

  • Documentation of test date, time, device, QC result, patient ID and results

  • Prompt and accurate reporting of results.

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B. Selection and Validations

Given that breath alcohol analyzers are point-of-care testing devices, the same requirements and principles and responsibilities that govern POCT should also be applicable.  Clinical laboratory personnel are the most experienced, trained, and qualified to evaluate analytical performance such as precision, accuracy, reliability, sensitivity and specificity.

Recommendation:  The laboratory should be involved in the selection, validation, and deployment of the breath alcohol devices used.

Discussion

The selection of breath alcohol devices should be based on performance and features that meet the requirements of clinical services.  Only devices listed in the National Highway Traffic Safety Administration (NHTSA) Conforming Product List should be used (40).  Table 4 lists the Committee’s recommendation for specific device specifications and desirable attributes for breath alcohol measurements in the ED.

Table 4.  Device Specifications and Desirable Attributes for Point-of Care Breath Alcohol Analysis

Device specifications

  • Accuracy and precision should meet or exceed performance required for intended clinical use

  • Prevents false positive results from acetone (up to 0.02% w/v)

  • Clinically appropriate analytical (reportable range in units of grams alcohol/100 mL of blood)

  • Environmental conditions appropriate for operation

Desirable attributes

  • Mistake-proof for ease of use by non-laboratory personnel

  • Procedural controls that monitor requisite operator steps and specimen delivery

  • Function checks that monitor components performance

  • Data logging capability

  • Printer and/or laboratory information management system interface

  • Battery operated devices should have a "low battery" indicator

The clinical laboratory has the responsibility to validate that the device performance meets or exceeds specifications prior to release of the technology for clinical use at near-patient sites.  This includes familiarization with the technology using vendor-supplied educational materials or programs, and adjust manufacture guidance to clinical service requirements.  Verification of device performance characteristics requires use of NHTSA-approved breath alcohol simulator and certified alcohol solutions or certified dry gas alcohol standards.  The analytical performance should be evaluated against experimental protocols established by the National Committee on Clinical Laboratory Standards (NCCLS)(41).  The accuracy and precision studies should be performed at clinically relevant alcohol concentrations.  The specificity should be challenged with aqueous solutions of volatiles (acetone, methanol, isopropanol) at concentrations likely to be encountered in clinical settings.  The calibration stability should be verified with suitable QC materials for each day the device is used.

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