Evaluation of Lyme serologic quantitative test indexes: High first-tier test index values predict positive second-tier result in standard and modified 2-tier Lyme testing algorithms.

OBJECTIVES: In this study, we evaluated the potential utility of reporting a quantitative Lyme serologic test index to improve the utility of results from first-tier Lyme assays. METHODS: Serum from consecutive samples sent to our laboratory for Lyme testing were tested on 2 commercial first-tier Lyme assays and evaluated to determine the probability of second-tier confirmation based on the serologic index value. RESULTS: For both assays, we identified an index value above which 100% of samples confirmed on second-tier testing using both standard and modified 2-tier testing algorithms. Lower rates of confirmation were observed for positive or equivocal samples with lower index values. CONCLUSION: The use of a Lyme test index value may eliminate the need for confirmatory testing on many positive first-tier samples, providing more rapid turnaround time to a definitive result. This practice would also increase efficiency in the clinical laboratory.

Evaluation of the Rapid Quidel Sofia 2 Lyme Immunoassay as a First-Tier Test in a Two-Tier Testing Algorithm for Lyme Disease: Comparison to the Zeus ELISA Borrelia VlsE1/pepC10 IgG/IgM Assay Followed by Immunoblot.

OBJECTIVES: Two-tiered serologic testing for Lyme disease is usually performed using an enzyme-linked immunosorbent assay (ELISA) as the first-tier test. The Quidel Sofia 2 Lyme test is a relatively new lateral flow method to provide more rapid turnaround time. We evaluated its performance in comparison to an established ELISA method. The test can be performed on demand rather than batching assays in a central laboratory. METHODS: We compared the Sofia 2 assay to the Zeus VlsE1/pepC10 IgG/IgM test in a standard two-tiered testing algorithm. RESULTS: Comparison of the Sofia 2 to the Zeus VlsE1/pepC10 IgG/IgM showed an overall agreement of 89.9% (κ statistic of 0.750, indicating "substantial agreement"). When the tests were followed by immunoblot in a two-tier algorithm, the agreement was 98.9% (κ statistic of 0.973, indicating "almost perfect" agreement). CONCLUSIONS: The Sofia 2 Lyme test performs well when compared with the Zeus VlsE1/pepC10 IgG/IgM in a two-tiered testing algorithm.

Measurement of High Sensitivity Troponin T in Patients with Early Stage Lyme Disease: Preliminary Evidence for Possible Subclinical Cardiac Involvement.

OBJECTIVE: In patients with early Lyme disease (ELD), cardiac involvement is known to occur in approximately 1% of patients. We measured high-sensitivity troponin T (hsTnT) in patients with early Lyme disease to evaluate the possibility of subclinical cardiac involvement. METHODS: We measured hsTnT in 41 patients with well characterized ELD. RESULTS: A total of 6/41 (14.6%) of patients exhibited hsTnT values above either the gender specific or gender neutral 99th percentile cutoff for a normal hsTnT. One patient had a value greater than the cutoff used for acute myocardial infarction. CONCLUSIONS: There are many possible explanations for increased hsTnT values in different types of patients in the absence of acute cardiac damage. Nonetheless our results raise the possibility that subclinical cardiac involvement may be more common in ELD than previously recognized. Further studies will be necessary to elucidate the significance of this finding.

Description of a point-of-care testing program in a large urban academic medical center: Technologies, management and program cost.

BACKGROUND: Point-of-care testing (POCT) is an important component of hospital-based and ambulatory laboratory testing. Despite its importance, there is relatively little in the peer reviewed literature describing the details of successful POCT programs. METHODS: Administrative records and test volumes from the Massachusetts General Hospital were compiled using POCT middleware (Telcor) and the hospital information system (Epic). Financial data was derived from vendor contracts and the hospital budget management system. RESULTS: Our POCT management team consists of 2.8 medical technologists and 0.1 medical director with an annual labor cost of $458,000 ($0.80/test). The team oversees quality and regulatory compliance for 143 testing sites. POCT constitutes 24 tests with an annual volume of over 573,000 tests (10.8% of all tests performed). Regular site inspections utilizing a compliance checklist with mandatory remedial action plans are employed. This approach has reduced inspection citations from 3.17 per testing site to 0.27 citations. The average cost of POCT tests is $1.89. CONCLUSIONS: POCT is widespread in our institution and comprises a significant percentage of the total test volume. A dedicated POCT team combined with regular site inspections using a comprehensive checklist facilitates regulatory compliance and quality testing.

Interpreting tricyclic antidepressant measurements in urine in an emergency department setting: comparison of two qualitative point-of-care urine tricyclic antidepressant drug immunoassays with quantitative serum chromatographic analysis.

Patients taking tricyclic antidepressants (TCA) can experience toxicity or severe side effects. As a rapid and less technically demanding alternative to quantitative serum analysis, most laboratories offer qualitative immunoassays to assist in the evaluation of a suspected TCA overdose. However, the relationship between quantitative serum and qualitative urine levels of TCA-related compounds and their metabolites has not been comprehensively studied. Serum high-performance liquid chromatography results were compared to the qualitative urine results using the Syva Rapid Test and the Biosite Triage. Serum concentrations of amitriptyline, desipramine, doxepin, imipramine, and nortriptyline ranging from subtherapeutic to toxic triggered a positive response on both urine immunoassay devices. On the other hand, neither immunoassay uniformly detected clomipramine, even at serum levels greater than the therapeutic range. False positives due to cyclobenzaprine were more common with the Biosite assay. For virtually all positive urine TCA findings, it was not possible to determine whether the positive results corresponded to subtherapeutic, therapeutic, supratherapeutic, or toxic serum concentrations. Because urine immunoassays are the only option for many laboratories analyzing specimens for TCAs (especially in an emergency setting), clinicians must understand the limitations and interpret results in conjunction with clinical findings and/or quantitation of serum levels.

Implementation of point-of-care testing in a general internal medicine practice: A confirmation study.

BACKGROUND: In a previous study we reported on the impact of point-of-care testing (POCT) on practice efficiency in an academic primary care practice that was established to develop new models of care delivery. Here we report a follow-on confirmation study in a more typical primary care practice in the community. METHODS: In this observational study with a retrospective comparison analysis we measured metrics of practice efficiency on two patient cohorts: those that did not receive POCT and those that did. RESULTS: In the patient cohort that received POCT there was a 99% reduction in letters to patients (p<0.001), a 75% decrease in calls to patients (not significant due to small numbers), a 50% reduction in follow-up tests per visit (p=0.044) and a 38% reduction in follow-up visits due to abnormal test results (p=0.178). Financial analysis including testing costs, revenues and efficiency gains to the practice demonstrated a net financial benefit of $11.90-14.74 per patient visit. CONCLUSIONS: Our data confirm the earlier published findings that POCT can improve metrics of practice efficiency in a primary care practice.

Elevation of myeloperoxidase in conjunction with cardiac-specific markers after marathon running.

Cardiac-related death has been reported following strenuous exercise, and biochemical markers predicting adverse outcomes would be useful. Despite the fact the myeloperoxidase (MPO) release may precede myocardial injury and identify at-risk patients earlier than traditional markers, information on the effects of marathon running on MPO levels is lacking. We measured MPO in conjunction with the creatine kinase MB fraction (CK-MB), myoglobin, troponin T (TnT), and N-terminal B-type natriuretic peptide (NT-proBNP) in 24 athletes before and after a marathon race. Of the 24 athletes, 22 (92%) had an increased MPO level, and the mean MPO level increased from 281.44 pmol/L to 785.21 pmol/L (P < .0001). Results for 14 (58%) of the athletes reached or exceeded the manufacturer's recommended clinical threshold. The increases in CK-MB, myoglobin, TnT, and NT-proBNP also reached statistical significance. Although the elevation in MPO most likely represents a systemic inflammatory response, the concurrent elevations in TnT and NT-proBNP suggest that myocardial injury cannot be excluded.

Laboratory testing for B-type natriuretic peptides (BNP and NT-proBNP): clinical usefulness, utilization, and impact on hospital operations.

B-type natriuretic peptides (BNP, NT-proBNP) are involved in cardiovascular remodeling, fluid and electrolyte balance, and myocardial response to coronary ischemia. Recent literature has demonstrated the usefulness of natriuretic peptides in the diagnosis of congestive heart failure (CHF). Further studies also have shown that B-type natriuretic peptides (BNPs) are useful to guide therapy in patients with established CHF and might be useful to estimate prognosis in patients with CHF and in those with left ventricular dysfunction due to acute coronary syndromes. Consequently, the majority of laboratories in the United States perform testing for BNP or its inactive aminoterminal fragment, NT-proBNP Most experts agree that blood levels of BNP and NT-proBNP can be used interchangeably, although important differences have been identified. Although the clinical usefulness of BNPs has been well described, few studies have reported data on the utilization of these markers or their impact on patient outcomes and hospital operations. This review describes the biochemical characteristics, clinical usefulness, patterns of utilization, and economic impact of laboratory testing for the BNPs.

Ischemia-modified albumin improves the usefulness of standard cardiac biomarkers for the diagnosis of myocardial ischemia in the emergency department setting.

We studied the role of ischemia-modified albumin (IMA) with standard biomarkers (myoglobin, creatine kinase-MB [CK-MB], troponin I [TnI]) in assessment of 200 patients with suspected myocardial ischemia admitted to the emergency department. Every case was reviewed by a cardiologist. A clinical diagnosis of ischemia was assigned and correlated with biomarker test results. Of the patients, 25 (13.0%) had myocardial ischemia. Receiver operating characteristic curves demonstrated IMA as highly sensitive but somewhat poorly specific for the presence of ischemia (area under curve, 0.63; P = .01). With a cut point of 90 U/mL, the Albumin Cobalt Binding Test had 80% sensitivity and 31% specificity for diagnosing ischemia and a negative predictive value of 92%. IMA was positive in 4 of 5 patients with electrocardiographic (ECG) evidence of ischemia and 16 of 20 patients with coronary ischemia but negative ECG. Among the same patients, the myoglobin-CK-MB-TnI triad had a sensitivity of 57%. The combination of IMA-myoglobin-CK-MB-TnI increased the sensitivity for detecting ischemia to 97%, with a negative predictive value of 92%. IMA is highly sensitive and has a high negative predictive value, which might improve the usefulness of standard biomarkers of myocardial ischemia.

Reevaluation of myoglobin for acute chest pain evaluation: would false-positive results on "first-draw" specimens lead to increased hospital admissions?

Myoglobin is an early marker of cardiac injury, although positive results occur in the absence of cardiac myonecrosis. We studied data for 537 patients admitted to the emergency department with symptoms suggestive of myocardial injury who underwent testing for troponin I (TnI), creatine kinase isoenzyme (CK-MB), and myoglobin at the point of care. Physicians were blinded to the myoglobin results. Myoglobin had a sensitivity of 69.7% and a negative predictive value of 97.4% for the diagnosis of acute coronary syndrome (ACS) on "first-draw" specimens. Receiver operating characteristic curve analysis suggested that myoglobin demonstrated optimal sensitivity for ACS, while TnI had optimal specificity. CK-MB was neither the most specific nor the most sensitive marker. More than 80% of the patients with false-positive myoglobin results were admitted to the hospital. These data invalidate concerns regarding the putative overtreatment effect of false-positive cases owing to myoglobin results. Furthermore, our data suggest that myoglobin is superior to CK-MB as an adjunct to TnI.

Patient satisfaction with point-of-care laboratory testing: report of a quality improvement program in an ambulatory practice of an academic medical center.

BACKGROUND: Point-of-care laboratory testing (POCT) offers reduced turnaround time and may facilitate medical decision-making and improve clinical operations. However, there is very little published data concerning the impact of POCT on patient satisfaction. METHODS: We implemented POCT for hemoglobin A1c, lipid panel and comprehensive metabolic panel in a primary care practice and monitored patient satisfaction with on-site testing using an anonymous survey. RESULTS: A total of 97 surveys (65% response rate) were reviewed. On a scale of 1 (poor) to 4 (excellent) the mean response to the question "Compared with your past experiences of physician office visits that did not have on-site testing please rank your overall level of satisfaction with today's office visit" was 3.96. In 34 surveys a free text comment was included which was uniformly very positive. CONCLUSIONS: Our study strongly indicates a high level of patient satisfaction with on-site POCT in a primary care setting.

Clinical evaluation of the i-STAT kaolin activated clotting time (ACT) test in different clinical settings in a large academic urban medical center: comparison with the Medtronic ACT Plus.

Historically, it has been difficult for hospitals to change methods for activated clotting time (ACT) testing because of differences in ACT values obtained with different instruments, wide differences in target ranges used in different procedures, and the difficulty of performing crossover studies at the bedside in critical care situations. There are limited published data comparing the i-STAT (Abbott Point of Care, Princeton, NJ) kaolin ACT with the Medtronic ACT Plus (Medtronic, Minneapolis, MN). The i-STAT system can perform ACT testing in addition to testing of a number of critical care analytes and may offer potential advantages over other ACT analyzers. Comparison of ACT values on 121 simultaneous split-sample tests yielded an R(2) of 0.88 with i-STAT = 0.79 Medtronic + 72.0. The Pearson correlation was R = 0.94, indicating statistically significant correlation between the 2 methods. Based on this comparison, we were able to implement the i-STAT ACT throughout our institution without changing target ranges for any individual procedure.

Does blood donor history accurately reflect the use of prescription medications? A comparison of donor history and serum toxicologic analysis.

BACKGROUND: Blood donor screening is performed to accomplish several goals, including donor safety during collection and recipient safety during transfusion. Donors taking certain medications such as teratogens or platelet-inhibiting drugs are deferred from donation. Studies investigating the accuracy of the donor history are limited and only provide data on select groups of drugs. This study compares the results of an extended serum toxicology analysis to the medication use reported on the donor questionnaire. STUDY DESIGN AND METHODS: Whole-blood samples were collected from 108 volunteer blood donors. A serum toxicology analysis was performed with high-performance liquid chromatography with photodiode array detection. The results were compared to those reported on the donor history questionnaire. RESULTS: The medication history was consistent with the reported medications in 96 (89%) donors. Serum toxicology testing detected medications that were not reported on the donor history form in 12 (11%) donors. Most of the donors who did not accurately report their medication use (8 or 67%) were taking psychotropic medications. CONCLUSION: Eleven percent of the donors did not fully disclose their recent medication history. Although none of the omitted medications would have been grounds for deferral, the finding of underreporting questions the reliability of donor screening. Despite a negative medication history, blood donor centers cannot assume that donors are medication-free. This study reveals a bias to omit psychotropic medications such as antidepressants and anxiolytics.

Measurement of organochlorines in commercial over-the-counter fish oil preparations: implications for dietary and therapeutic recommendations for omega-3 fatty acids and a review of the literature.

CONTEXT: The consumption of fish high in omega-3 fatty acids is advocated by the American Heart Association to decrease the risk of coronary artery disease. However, fish contain environmental toxins such as mercury, polychlorinated biphenyls, and organochlorine pesticides, which may negate the beneficial cardiovascular effects of fish meals. Toxin levels vary depending on both the fish source and the specific toxin, and neither farm-raised nor wild fish are toxin free. Fish oil supplements also prevent the progression of coronary artery disease and reduce cardiovascular mortality. However, only sparse data exist on the level of toxins in fish oil. In a previous study we showed that the amount of mercury in 5 over-the-counter brands of fish oil was negligible. OBJECTIVE: To determine the concentrations of polychlorinated biphenyls and other organochlorines in 5 over-the-counter preparations of fish oil. DESIGN: The contents of 5 commercial fish oil brands were sent for organochlorine analysis. RESULTS: The levels of polychlorinated biphenyls and organochlorines were all below the detectable limit. CONCLUSIONS: Fish oil supplements are more healthful than the consumption of fish high in organochlorines. Fish oils provide the benefits of omega-3 fatty acids without the risk of toxicity. In addition, fish oil supplements have been helpful in a variety of diseases, including bipolar disorder and depression.