Definitions of the levels of evidence (I—III) and grades of the recommendation (A, B, C, I) are presented at the end of the "Major Recommendations" field.
Note from the National Academy of Clinical Biochemistry (NACB) and the National Guideline Clearinghouse (NGC): The Laboratory Medicine Practice Guidelines (LMPG) evidence-based practice for point-of-care testing sponsored by the NACB have been divided into individual summaries covering disease- and test-specific areas. In addition to the current summary, the following are available:
Sample Preparation and Testing
Are there significant differences between point-of-care testing (POCT) devices?
Guideline 83. Once the potential need for POCT is established, a careful evaluation should be conducted by the staff in the environment in which the devices are to be used and on the relevant population.
Strength/consensus of recommendation: A
Level of evidence: II
What analytical accuracy issues affect the use of POCT devices?
Guideline 84. Users of POCT devices should understand any limitations of the devices. This should include the statistical and analytical sensitivity, specificity, and nomenclature of the devices to facilitate their appropriate use.
Strength/consensus of recommendation: A
Level of evidence: I
What knowledge of cross-reactivity of POCT devices is required for their use?
Guideline 85. Users of POCT devices need to be aware of any known interferences from drugs or metabolites that could affect results interpretation.
Strength/consensus of recommendation: A
Level of evidence: I
What are the chief quality issues associated with POCT?
Guideline 86. Purchasers of POCT devices should ensure that users are correctly trained in their use, application, and interpretation. This training should include quality issues and recognition of any device limitations.
Strength/consensus of recommendation: A
Level of evidence: I
What knowledge of sample adulteration is required for the use of POCT devices?
Guideline 87. Users of POCT devices need to be aware of any known interferences from chemicals and other methods of adulteration/manipulation that could affect results interpretation. Procedures need to be adopted within a protocol framework to ensure specimens are tamper free. In critical situations, the type of POCT chosen should enable the tester to detect manipulation by the donor.
Strength/consensus of recommendation: A
Level of evidence: II
Are there significant differences between POCT and central laboratory testing (CLT)?
Guideline 88. POCT for drugs of abuse (DOA) or ethanol may provide adequate information for clinical intervention. Where a definitive penal or legal action is to be taken, laboratory confirmation is mandatory.
Strength/consensus of recommendation: A
Level of evidence: I
Are there significant differences between POCT and CLT?
Guideline 89. POCT screening can be effective, provided quality and data recording issues are addressed. The cost/economic impact needs consideration before introduction. Recording of data is vital, and a legally defensible approach is advised.
Strength/consensus of recommendation: A
Level of evidence: III
Are there significant differences between POCT and CLT?
Guideline 90. There is insufficient evidence for or against specimen stability as a justification for testing location.
Strength/consensus of recommendation: I
Level of evidence: III
Is there an evidence base to confirm that POCT devices perform adequately at detection limits/cutoffs?
Guideline 91. The cutoff(s) should be considered in the selection of a device because these will affect the number of samples requiring confirmation. The statistical likelihood of obtaining a negative result for a sample containing drug near the cutoff should be defined by the manufacturer and presented so that the user who is not a laboratorian can understand the implication of false-negative results. Validation studies during selection and implementation should include testing of the defined cutoff.
Strength/consensus of recommendation: A
Level of evidence: III
What is the impact of quality assurance and quality control (QC) on POCT screening?
Guideline 92. All users of POCT devices must use QC material and participate in external quality assurance (EQA) schemes.
Strength/consensus of recommendation: A
Level of evidence: I
Guideline 93. The decision to use POCT should be a formal corporate decision after a formal evaluation process of the options to ensure fitness for purpose. Only authorized, trained, competency-assessed staff should be allowed to perform POCT within an agreed governance arrangement.
Strength/consensus of recommendation: A
Level of evidence: III
Are there specific quality issues around interpretation of results obtained from POCT devices?
Guideline 94. Procedures must be agreed on and in place to ensure only those recognized by the organization as being competent to interpret POCT results do so. The consequences to the patient/client, analyst, and corporation must be recognized.
Strength/consensus of recommendation: A
Level of evidence: III
Are there specific quality issues for POCT vs CLT?
Guideline 95. All analyses, whether POCT or CLT, must be subject to QC and quality assurance. This should encompass a quality system that includes effective training, recordkeeping, and review.
Strength/consensus of recommendation: A
Level of evidence: II
Use of POCT for DOA in the Clinical Setting
What is the effect on outcome of rapid drug screening in emergency departments (EDs)?
Guideline 96. Although immediacy of POC drug testing results is hypothesized to be useful in an ED, this has not been systematically documented in outcome studies. Therefore, no recommendation can be made at this time.
Strength/consensus of recommendation: C
Level of evidence: I
Guideline 97. There is little cumulated outcome literature to support POCT for DOA in outpatient clinic and outreach clinical settings. Although there are situations where utilization of POCT may enable faster decision making regarding patient disposition, as in an addiction clinic, there is little evidence to support this, and therefore introduction and use should be circumspect.
Strength/consensus of recommendation: I
Level of evidence: III
Guideline 98. There are no outcome studies that support the use of POCT for DOA in obstetric or pain clinics. Although testing for DOA in these settings is often clinically indicated, there is no evidence of added benefit from performing the test at the point of care.
Strength/consensus of recommendation: I
Level of evidence: III
Guideline 99. In clinical settings, the user must be aware of the possibility of sample adulteration/manipulation.
Strength/consensus of recommendation: I
Level of evidence: III
What is the evidence from the literature on the need for confirmation from different population groups?
Guideline 100. Clear guidelines should be developed regarding the need to confirm positive test results using a more sensitive and specific laboratory method, particularly for situations where definitive punitive action will be taken based on the result. In clinical settings where treatment may be based upon unconfirmed results, staff using the data should be educated with respect to the limitations of the testing.
Strength/consensus of recommendation: A
Level of evidence: I
Urine versus Alternative Matrices
Does the matrix (blood/serum/plasma, saliva, sweat, urine, meconium) affect acceptability for POCT for drugs, and what is the evidence supporting this recommendation?
Guideline 101. Urine is the best established matrix for POCT. Cutoff levels, interferences, and interactions have been established and studied more in urine than in testing with other matrices.
Strength/consensus of recommendation: A
Level of evidence: I
Guideline 102. If alternate matrices are to be used for POCT, the antibodies and cutoffs must be optimized to detect the parent drug or metabolite most abundant in that matrix. Evidence of accuracy and precision must be documented. Sample sites and collection methods for oral fluid, sweat, and breath must be standardized. Sweat sample contamination issues must be resolved before sweat can be considered an acceptable testing matrix.
Strength/consensus of recommendation: I
Level of evidence: II
Guideline 103. Reports using oral fluid for drug screening by POCT demonstrate unsatisfactory results for certain drugs, especially for opiates, delta-9-tetrahydrocannabinol (THC), and benzodiazepine detection. There is a lack of evidence regarding limitations of oral fluid testing.
Strength/consensus of recommendation: C
Level of evidence: II
Nonclinical Applications of POCT for DOA and Ethanol
What is the effect of POCT devices on the outcome of drug testing in nonclinical settings?
Guideline 104. Although drug testing in nonclinical settings may have an overall positive effect of identifying and discouraging drug abuse, there is no evidence that point-of-care drug testing offers any incremental benefit towards those outcomes when compared to conventional testing in a referral laboratory. There may be logistical, and perhaps economic, advantages to point-of-care drug testing, but these benefits are not generalizable.
Strength/consensus of recommendation: I
Level of evidence: II
Are POCT devices reliable for nonclinical applications?
Guideline 105. Although generally reliable in comparison to automated screening methods for DOA, point-of-care devices do not have sufficient specificity to be used for nonclinical applications, and results may be subject to legal challenge unless positive results are confirmed by a definitive method.
Strength/consensus of recommendation: A
Level of evidence: I
How well do nonlaboratory personnel use POCT devices for DOA in urine for definitive actions in nonclinical settings?
Guideline 106. When used by trained laboratory personnel, there is evidence that the current POCT devices for urine drug screening produce results that are comparable to laboratory-based screening methods. When used by trained, nonlaboratory personnel, results are poorer. Policy makers need to decide the acceptable benefit/risk ratio they seek in taking definitive actions; advice from laboratorians should be sought.
Strength/consensus of recommendation: A
Level of evidence: II
Other Issues
Are POCT panels of drugs preferred over single tests?
Guideline 107. If opting to use POCT panels, consider the prevalence of use in the population to be tested for all the drug types on the panel; consider the benefits of single POCT devices in terms of flexibility and cost. Balance this against the breadth of testing available from a central laboratory.
Strength/consensus of recommendation: I
Level of evidence: III
Is there evidence for an economic impact of POCT for DOA and ethanol in any context?
Guideline 108. Independent studies to assess the economic value of POCT for drug testing are urgently needed, particularly given the multimillion dollar nature of the market.
Strength/consensus of recommendation: I
Level of evidence: III
Definitions:
Levels of Evidence
- Evidence includes consistent results from well-designed, well-conducted studies in representative populations.
- Evidence is sufficient to determine effects, but the strength of the evidence is limited by the number, quality, or consistency of the individual studies; generalizability to routine practice; or indirect nature of the evidence.
- Evidence is insufficient to assess the effects on health outcomes because of limited number or power of studies, important flaws in their design or conduct, gaps in the chain of evidence, or lack of information.
Strength of Recommendations
A - The National Academy of Clinical Biochemistry (NACB) strongly recommends adoption; there is good evidence that it improves important health outcomes and concludes that benefits substantially outweigh harms.
B - The NACB recommends adoption; there is at least fair evidence that it improves important health outcomes and concludes that benefits outweigh harms.
C - The NACB recommends against adoption; there is evidence that it is ineffective or that harms outweigh benefits.
I - The NACB concludes that the evidence is insufficient to make recommendations; evidence that it is effective is lacking, of poor quality, or conflicting, and the balance of benefits and harms cannot be determined.
