Prevalence of Levamisole in Urine Toxicology Screens Positive For
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LETTERS portable, handheld ultrasound units are now available. In clinical settings, the marginal benefit of the added diagnos- 1988, Filly,2 in an editorial, called ultrasound the stetho- tic information likely does not justify the added cost of the scope of the future but was concerned about its use in un- device, the time it adds to the physical examination, or the trained hands. In 2002, Dodd3 encouraged teaching the tech- cost of false-positive and incidental findings requiring ad- nique of ultrasound usage to medical students beginning in ditional follow-up. the gross anatomy laboratory and ending in ward rounds We would like to emphasize that the potential for bring- and senior electives. In 2003, Greenbaum4 projected that ing new technology to the physical examination should not in the near future “medical students will also be buying a be viewed as a substitute for developing strong physical ex- ‘sonoscope’” in addition to a stethoscope. He envisioned amination skills. The routine physical examination remains the sonoscope as enhancing the physical examination of all part of standard practice because it is quick, cheap, and readily patients. With the advent of smaller, better-quality, and less- available. It also helps to formulate hypotheses and can al- expensive machines, and medical schools beginning to pro- low a physician to quickly rule in or out competing diag- vide technical training for their students, the use of point- noses. For the most part, the tips and maneuvers that we raised of-care ultrasound is increasing, with applications in physical in our article are simple, inexpensive, and easily mastered. diagnosis, screening, and guiding procedures.5 Small, por- Using such techniques to strengthen physical examination table, handheld ultrasound units are now inexpensive enough skills and promoting the judicious use of imaging technol- for this to be a reasonable addition to a clinician’s everyday ogy may allow physicians to provide high-quality patient care armamentarium. Little, however, has been written about use while insulating against rising health care costs. of this technology in obese patients or about the upper lim- Ann Willman Silk, MD, MA its of its usefulness. Because ultrasound penetrates fluid and [email protected] solid organs well, it may be useful in the physical exami- Internal Medicine Residency Program nation of the obese patient. University of Pittsburgh Medical Center Pittsburgh, Pennsylvania G. David Dixon, MD [email protected] Kathleen M. McTigue, MD, MPH, MS Department of Radiology Center for Research on Health Care Saint Luke’s Hospital University of Pittsburgh Kansas City, Missouri Pittsburgh Conflicts of Interest Disclosures: Both authors have completed and submitted the ICMJE Form for Disclosure of Potential Conflicts of Interest and none were re- Conflicts of Interest Disclosures: The author has completed and submitted the ported. ICMJE Form for Disclosure of Potential Conflicts of Interest and none were re- ported. 1. Filly RA. Is it time for the sonoscope? J Ultrasound Med. 2003;22(4):323- 325. 1. Silk AW, McTigue KM. Reexamining the physical examination for obese patients. 2. Johnson C. Mini ultrasound revolutionizing emergency medicine. KGO-TV news, JAMA. 2011;305(2):193-194. San Francisco. http://abclocal.go.com/kgo/story?section=news/health&id= 2. Filly RA. Ultrasound: the stethoscope of the future, alas. Radiology. 1988; 7325735. Accessed April 6, 2011. 167(2):400. 3. Dodd GD. Handheld sonography and the big picture. SRU Newsletter: Octo- ber 2002. Society of Radiologists in Ultrasound. 4. Greenbaum LD. It is time for the sonoscope. J Ultrasound Med. 2003;22 (4):321-322. 5. Moore CL, Copel JA. Point-of-care ultrasonography. N Engl J Med. 2011; RESEARCH LETTER 364(8):749-757. Prevalence of Levamisole in Urine In Reply: We agree with Dr Dixon that technological ad- Toxicology Screens Positive for Cocaine vances, such as sonoscopes, may be able to alleviate some in an Inner-City Hospital of the limitations of the physical examination for obese pa- tients. However, we have concerns about the potential wide- To the Editor: Cocaine use is prevalent in the United States. spread use of the sonoscope in routine clinical practice. For Recently, we encountered multiple patients at our institu- example, handheld ultrasound machines have not yet been tion with unexplained agranulocytosis or cutaneous vascu- well studied, especially in the generalist’s hands. The qual- litis. All had used cocaine contaminated with levamisole. ity of an imaging test depends on the performance and the Although levamisole is known to be present in cocaine speci- interpretation, and sonography is a difficult imaging tech- mens, it is not clear how often levamisole exposure from nique to master.1 If an examiner has a suspicion about an cocaine use leads to systemic levamisole absorption. The ob- abnormality on physical examination, it may be preferable jective of this study was to determine the prevalence of le- to order an ultrasound study performed by someone who vamisole in urine toxicology screens positive for cocaine in is properly trained. Another problem with sonoscopes is the a 500-bed public safety-net hospital with 160 000 unique cost. Although the price of a handheld device has de- patient users in 2010. creased over the past several years (in 2003 the cost was more Methods. Consecutive urine toxicology samples received than $15 000 compared with present-day costs that range by the hospital laboratory that tested positive for cocaine from $4000 to $10 000),2 the cost remains high. For many by immunoassay (Syva EMIT II; Siemens Healthcare Diag- ©2011 American Medical Association. All rights reserved. JAMA, April 27, 2011—Vol 305, No. 16 1657 Downloaded From: https://jamanetwork.com/ on 09/26/2021 LETTERS nostics, Deerfield, Illinois) were sent to the Colorado Depart- some were missed. Given the high prevalence of levami- ment of Public Health for comprehensive drug analysis (in- sole in the cocaine supply, physicians should consider le- cluding levamisole) using gas chromatography–mass vamisole exposure in cocaine users with unexplained agranu- spectroscopy (GC/MS). Proportions of samples (and 95% locytosis, leukoencephalopathy, or cutaneous vasculitis. confidence intervals [CIs]) positive for cocaine, levami- Jennie A. Buchanan, MD sole, and other drugs of abuse were calculated. The study [email protected] was approved by our institutional review board with a waiver Department of Emergency Medicine of informed consent. No patient identifying, demographic, Denver Health and Hospital Authority and the Rocky Mountain or clinical data were collected. JMP version 8.0 was used for Poison and Drug Center statistical analysis (SAS Institute. Cary, North Carolina). Denver, Colorado Results. Three hundred samples were obtained from April Kennon Heard, MD Denver Health and Hospital Authority and the Rocky Mountain 14, 2010, to July 13, 2010. Although all of the samples were Poison and Drug Center positive for cocaine by immunoassay,only 249 of 300 samples Denver, Colorado (83%; 95% CI, 78%-87%) were positive for cocaine by GC/ Cynthia Burbach, BS, MPA MS. Of the samples positive for cocaine by GC/MS, 194 of Department of Public Health 249 (78%; 95% CI, 73%-83%) contained levamisole. Of the Denver, Colorado samples negative for cocaine by GC/MS, 9 of 51 (18%; 95% Michael L. Wilson, MD CI, 10%-30%) contained levamisole. The overall propor- Department of Pathology tion of samples positive for levamisole was 203 of 300 (68%; Denver Health and Hospital Authority 95% CI, 63%-73%). The most common other drugs found Denver, Colorado in the specimens were opioid analgesics (methadone, n=134, Richard Dart, MD, PhD 45% of samples; codeine, n=50, 16%; heroin/6- Denver Health and Hospital Authority and the Rocky Mountain Poison and Drug Center monoacetylmorphine, n=17, 6%; morphine, n=15, 5%; and Denver, Colorado oxycodone, n=15, 5%). Author Contributions: Dr Buchanan had full access to all of the data in the study Comment. This study demonstrates that levamisole used and takes responsibility for the integrity of the data and the accuracy of the data to adulterate cocaine was systemically absorbed by cocaine analysis. Study concept and design: Buchanan, Heard, Burbach, Wilson, Dart. users and, in 1 institution, was common in urine samples Acquisition of data: Buchanan, Heard, Burbach, Wilson. positive for cocaine. The 17% of samples positive for co- Analysis and interpretation of data: Buchanan, Heard, Burbach. Drafting of the manuscript: Buchanan, Burbach. caine by immunoassay but negative by GC/MS may be due Critical revision of the manuscript for important intellectual content: Buchanan, to degradation of cocaine metabolites during storage. The Heard, Burbach, Wilson, Dart. low incidence of levamisole present in samples alone with- Statistical analysis: Buchanan, Heard, Burbach. Obtained funding: Buchanan, Burbach, Dart. out cocaine may indicate a more rapid degradation or ex- Administrative, technical, or material support: Buchanan, Burbach, Wilson. cretion of cocaine metabolites compared with levamisole Study supervision: Dart. Conflict of Interest Disclosures: All authors have completed and submitted the ICMJE metabolites. Form for Disclosure of Potential Conflicts of Interest and none were reported. Although developed as an antihelminthic agent, levami- Funding/Support: This work was supported by an intramural research grant from the Rocky Mountain Poison and Drug Center. Dr Heard was supported by