Use of Spoligotype Analysis to Detect Laboratory Cross-Contamination

2000 ◽  
Vol 21 (8) ◽  
pp. 525-527 ◽  
Author(s):  
Beth Nivin ◽  
Jeffrey Driscoll ◽  
Tom Glaser ◽  
Pablo Bifani ◽  
Sonal Munsiff
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Dna Fingerprinting ◽  
False Positive ◽  
Cross Contamination

Spoligotype analysis identified false-positive isolates ofMycobacterium tuberculosiscaused by laboratory cross-contamination. Spoligotyping is faster, is less expensive than DNA fingerprinting, and can be used with a variety of media. Patients were reevaluated and had medications discontinued as a result of this investigation. Months of unnecessary patient follow-up and treatment were avoided.

The Effect of Changes in Laboratory Practices on the Rate of False-Positive Cultures for Mycobacterium tuberculosis

2001 ◽  
Vol 125 (9) ◽  
pp. 1213-1216
Author(s):  
Peter E. Breese ◽  
William J. Burman ◽  
Mary Hildred ◽  
Barbara Stone ◽  
Michael L. Wilson ◽  
...  
Keyword(s):  
Mycobacterium Tuberculosis ◽  
False Positive ◽  
Positive Culture ◽  
Control Program ◽  
Dna Fingerprint ◽  
Cross Contamination ◽  
Convenience Sample ◽  
Hospital System ◽  
Policies And Procedures ◽  
Public Hospital System

Abstract Context.—False-positive cultures for Mycobacterium tuberculosis have been found in nearly all DNA fingerprinting studies, but the effectiveness of interventions to reduce cross-contamination has not been evaluated. Objective.—To evaluate whether changes in laboratory policies and procedures reduced the rate of false-positive cultures. Design.—Retrospective study of isolates with matching DNA fingerprints. Setting.—A mycobacteriology laboratory serving an urban tuberculosis control program and public hospital system. Patients.—All M tuberculosis isolates processed from July 1994 to December 1999. Methods.—Isolates were fingerprinted using IS6110; pTBN12 was used to fingerprint isolates having fewer than 6 copies of IS6110. We further evaluated all patients having only one positive culture whose DNA fingerprint matched that of another isolate processed in the laboratory within 42 days. Interventions.—We changed laboratory policy to reduce the number of smear-positive specimens processed and changed laboratory procedures to minimize the risk of cross-contamination during batch processing. Main Outcome Measure.—The rate of false-positive cultures. Results.—Of 13 940 specimens processed during the study period, 630 (4.5%) from 184 patients and 48 laboratory proficiency specimens grew M tuberculosis. There were no cases (0/184) of probable or definite cross-contamination, compared with the 4% rate (8/199) identified in our previous study (P = .008). We also fingerprinted a convenience sample of isolates from other laboratories in Denver; 13.6% (3/22) of these were false-positive, a rate similar to the 11.9% rate (5/42) identified for other laboratories in our previous study (P = .84). Conclusions.—Laboratory cross-contamination decreased significantly after relatively simple, inexpensive changes in laboratory policies and practices. Cross-contamination continued to occur in other laboratories in Denver.

scholarly journals Inactivation of Mycobacterium tuberculosis for DNA Typing Analysis

1999 ◽  
Vol 37 (7) ◽  
pp. 2350-2351 ◽  
Author(s):  
P. Bemer-Melchior ◽  
H. B. Drugeon
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Dna Fingerprinting ◽  
Dna Extraction ◽  
Culture Media ◽  
Dna Typing ◽  
Epidemiological Studies ◽  
Dna Integrity ◽  
Cross Contamination ◽  
Laboratory Staff ◽  
A New Technique

DNA fingerprinting analysis of Mycobacterium tuberculosis is used for epidemiological studies and the control of laboratory cross-contamination. Because standardized procedures are not entirely safe for mycobacteriology laboratory staff, the paper proposes a new technique for the processing of specimens. The technique ensures the inactivation of M. tuberculosis before DNA extraction without the loss of DNA integrity. The control of inactivated cultures should be rigorous and should involve the use of two different culture media incubated for at least 4 months.

scholarly journals False-Positive Mycobacterium tuberculosis Detection: Ways to Prevent Cross-Contamination

2020 ◽  
Vol 83 (3) ◽  
pp. 211-217
Author(s):  
Mohammad Asgharzadeh ◽  
Mahdi Asghari Ozma ◽  
Jalil Rashedi ◽  
Behroz Mahdavi Poor ◽  
Vahid Agharzadeh ◽  
...  
Keyword(s):  
Mycobacterium Tuberculosis ◽  
False Positive ◽  
Cross Contamination

Improving diagnosis of acute appendicitis with atypical findings by Tc-99m HMPAO leukocyte scan

2002 ◽  
Vol 41 (01) ◽  
pp. 37-41 ◽  
Author(s):  
S. Shung-Shung ◽  
S. Yu-Chien ◽  
Y. Mei-Due ◽  
W. Hwei-Chung ◽  
A. Kao
Keyword(s):  
Acute Appendicitis ◽  
False Positive ◽  
False Positive Rate ◽  
Accurate Method ◽  
Clinical Findings ◽  
Pathological Findings ◽  
Lower Quadrant ◽  
Predictive Values ◽  
Positive Rate

Summary Aim: Even with careful observation, the overall false-positive rate of laparotomy remains 10-15% when acute appendicitis was suspected. Therefore, the clinical efficacy of Tc-99m HMPAO labeled leukocyte (TC-WBC) scan for the diagnosis of acute appendicitis in patients presenting with atypical clinical findings is assessed. Patients and Methods: Eighty patients presenting with acute abdominal pain and possible acute appendicitis but atypical findings were included in this study. After intravenous injection of TC-WBC, serial anterior abdominal/pelvic images at 30, 60, 120 and 240 min with 800k counts were obtained with a gamma camera. Any abnormal localization of radioactivity in the right lower quadrant of the abdomen, equal to or greater than bone marrow activity, was considered as a positive scan. Results: 36 out of 49 patients showing positive TC-WBC scans received appendectomy. They all proved to have positive pathological findings. Five positive TC-WBC were not related to acute appendicitis, because of other pathological lesions. Eight patients were not operated and clinical follow-up after one month revealed no acute abdominal condition. Three of 31 patients with negative TC-WBC scans received appendectomy. They also presented positive pathological findings. The remaining 28 patients did not receive operations and revealed no evidence of appendicitis after at least one month of follow-up. The overall sensitivity, specificity, accuracy, positive and negative predictive values for TC-WBC scan to diagnose acute appendicitis were 92, 78, 86, 82, and 90%, respectively. Conclusion: TC-WBC scan provides a rapid and highly accurate method for the diagnosis of acute appendicitis in patients with equivocal clinical examination. It proved useful in reducing the false-positive rate of laparotomy and shortens the time necessary for clinical observation.

The incidence of false-positive cultures for Mycobacterium tuberculosis.

1997 ◽  
Vol 155 (1) ◽  
pp. 321-326 ◽  
Author(s):  
W J Burman ◽  
B L Stone ◽  
R R Reves ◽  
M L Wilson ◽  
Z Yang ◽  
...  
Keyword(s):  
Mycobacterium Tuberculosis ◽  
False Positive

scholarly journals The KELT Follow-up Network and Transit False-positive Catalog: Pre-vetted False Positives for TESS

2018 ◽  
Vol 156 (5) ◽  
pp. 234 ◽  
Author(s):  
Karen A. Collins ◽  
Kevin I. Collins ◽  
Joshua Pepper ◽  
Jonathan Labadie-Bartz ◽  
Keivan G. Stassun ◽  
...  
Keyword(s):  
False Positive ◽  
False Positives

scholarly journals Role of Hepatobiliary Scintigraphy and Ultrasonography in the Diagnosis of Biliary Atresia in Infant with Neonatal Jaundice – Experiences in NINMAS

2017 ◽  
Vol 18 (1) ◽  
pp. 51-53
Author(s):  
Nasreen Sultana ◽  
Zeenat Jabin ◽  
Md Bashir ◽  
Rahima Parveen ◽  
Shamim MF Begum ◽  
...  
Keyword(s):  
Retrospective Study ◽  
Gall Bladder ◽  
Biliary Atresia ◽  
False Positive ◽  
Hepatic Dysfunction ◽  
Hepatobiliary Scintigraphy ◽  
Hida Scan ◽  
Complementary Role

Objective: The purpose of this study was to determine whether gall bladder visualization can help to exclude the biliary atresia in hepatobiliary scintigraphic studies of infants with persistent jaundice.Methods: This is a retrospective study carried out at the National Institute of Nuclear Medicine and Allied Sciences (NINMAS). Study subjects include infants with neo-natal jaundice who underwent Hepatobiliary scintigraphies for suspected biliary atresia and study period was 2 years. Food was withheld for 4 hours before the examination. Anterior images of liver and gall bladder were taken after i/v administration of 2 -3 mci 99m Tc labeled Brida (HIDA) at 5 min interval for 2 hours then at 4 hours and 24 hours. Non-visualization of bowel activity in HIDA scan in 24hours delayed images was considered as cases of diagnosis of biliary atresia.Results: Thirty-six patients were included in this retrospective study. Patent biliary channels was seen by scintigraphies in 17(47%) patients and biliary atresia was seen in 19(52%) patients. By abdominal US non- visualization of gall bladder were found in 25(69%) cases and gall bladder visualized in 11(30%) cases. Eight (22%) of 36 patients had biopsy confirmed biliary atresia; all of these had positive scintigraphies and (60%) had positive sonographic findings. Among the 5 false-positive scintigraphies caused by hepatic dysfunction and 2 had normal sonography. Thirty-six patients had periscintigraphic sonography. There were 25/36 (61%) abnormal studies, which included cases with small gallbladder (n = 8) and non-visualized gallbladder (n = 17), but not periportal fibrosis.Conclusion: Gall bladder was usually visible on Hepatobiliary scintigraphy of fasting patients with biliary patency.  Both hepatobiliary scintigraphy and sonography are currently the standard imaging investigations for suspected biliary atresia. The complementary role, in which scintigraphy and sonography are important, and recommend follow-up imaging reassessment before making definitive surgical decisions. This will serve to decrease the frequency of false-positive imaging diagnoses of biliary atresia, and hence, avoid unnecessary surgeries.Bangladesh J. Nuclear Med. 18(1): 51-53, January 2015

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