HIV false positive screening serology due to sample contamination reduced by a dedicated sample and platform in a high prevalence environment

Automated testing of HIV serology on clinical chemistry analysers has become common. High sample throughput, high HIV prevalence and instrument design could all contribute to sample cross-contamination by microscopic droplet carry-over from seropositive samples to seronegative samples resulting in false positive low-reactive results. Following installation of an automated shared platform at our public health laboratory, we noted an increase in low reactive and false positive results. Subsequently, we investigated HIV serology screening test results for a period of 21 months. Of 485 initially low positive or equivocal samples 411 (85%) tested negative when retested using an independently collected sample. As creatinine is commonly requested with HIV screening, we used it as a proxy for concomitant clinical chemistry testing, indicating that a sample had likely been tested on a shared high-throughput instrument. The contamination risk was stratified between samples passing the clinical chemistry module first versus samples bypassing it. The odds ratio for a false positive HIV serology result was 4.1 (95% CI: 1.69–9.97) when creatinine level was determined first, versus not, on the same sample, suggesting contamination on the chemistry analyser. We subsequently issued a notice to obtain dedicated samples for HIV serology and added a suffix to the specimen identifier which restricted testing to a dedicated instrument. Low positive and false positive rates were determined before and after these interventions. Based on measured rates in low positive samples we estimate that before the intervention, of 44 117 HIV screening serology samples, 753 (1.71%) were false positive, declining to 48 of 7 072 samples (0.68%) post-intervention (p<0.01). Our findings showed that automated high throughput shared diagnostic platforms are at risk of generating false-positive HIV test results, due to sample contamination and that measures are required to address this. Restricting HIV serology samples to a dedicated platform resolved this problem.

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1120. Impact of Training Residents to Improve HIV Screening in a Teaching Hospital in Mexico City

Open Forum Infectious Diseases ◽

10.1093/ofid/ofaa439.1306 ◽

2020 ◽

Vol 7 (Supplement_1) ◽

pp. S590-S590

Author(s):

Lorena Guerrero-Torres ◽

Isaac Núñez-Saavedra ◽

Yanink Caro-Vega ◽

Brenda Crabtree-Ramírez

Keyword(s):

Emergency Department ◽

Time Series ◽

Hiv Testing ◽

Teaching Hospital ◽

Educational Intervention ◽

Temporal Trends ◽

Hiv Screening ◽

Hiv Diagnosis ◽

Post Intervention ◽

Hiv Test

Abstract Background Among 230,000 people living with HIV in Mexico, 24% are unaware of their diagnosis, and half of newly diagnosed individuals are diagnosed with advanced disease. Early diagnosis is the goal to mitigate HIV epidemic. Missed opportunities may reflect a lack of clinicians’ consideration of HIV screening as part of routine medical care. We assessed whether an educational intervention on residents was effective to 1) improve the knowledge on HIV screening; 2) increase the rate of HIV tests requested in the hospitalization floor (HF) and the emergency department (ED); and 3) increase HIV diagnosis in HF and ED. Methods Internal Medicine and Surgery residents at a teaching hospital were invited to participate. The intervention occurred in August 2018 and consisted in 2 sessions on HIV screening with an expert. A questionnaire was applied before (BQ) and after (AQ) the intervention, which included HIV screening indications and clinical cases. The Institutional Review Board approved this study. Written informed consent was obtained from all participants. BQ and AQ scores were compared with a paired t-test. To evaluate the effect on HIV test rate in the HF and ED, an interrupted time series analysis was performed. Daily rates of tests were obtained from September 2016 to August 2019 and plotted along time. Restricted cubic splines (RCS) were used to model temporal trends. HIV diagnosis in HF and ED pre- and post-intervention were compared with a Fisher’s exact test. A p< 0.05 was considered significant. Results Among 104 residents, 57 participated and completed both questionnaires. BQ score was 79/100 (SD±12) and AQ was 85/100 (SD±8), p< .004. Time series of HIV testing had apparent temporal trends (Fig 1). HIV test rate in the HF increased (7.3 vs 11.1 per 100 episodes) and decreased in the ED (2.6 vs 2.3 per 100 episodes). HIV diagnosis increased in the HF, from 0/1079 (0%) pre-intervention to 5/894 (0.6%) post-intervention (p< .018) (Table 1). Fig 1. HIV test rates. Gray area represents post-intervention period. Table 1. Description of episodes, HIV tests and rates pre- and post-intervention in the Emergency Department and Hospitalization Floor. Conclusion A feasible educational intervention improved residents’ knowledge on HIV screening, achieved maintenance of a constant rate of HIV testing in the HF and increased the number of HIV diagnosis in the HF. However, these results were not observed in the ED, where administrative barriers and work overload could hinder HIV screening. Disclosures All Authors: No reported disclosures

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Potential for false positive HIV test results with the serial rapid HIV testing algorithm

BMC Research Notes ◽

10.1186/1756-0500-5-154 ◽

2012 ◽

Vol 5 (1) ◽

Cited By ~ 25

Author(s):

Steven Baveewo ◽

Moses R Kamya ◽

Harriet Mayanja-Kizza ◽

Robin Fatch ◽

David R Bangsberg ◽

...

Keyword(s):

Hiv Testing ◽

False Positive ◽

Test Results ◽

Rapid Hiv Testing ◽

Hiv Test ◽

Testing Algorithm

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An Electronic Alert for HIV Screening in the Emergency Department Increases Screening but not the Diagnosis of HIV

Applied Clinical Informatics ◽

10.4338/aci-2013-09-ra-0075 ◽

2014 ◽

Vol 05 (01) ◽

pp. 299-312 ◽

Cited By ~ 7

Author(s):

N. Liu ◽

J. Sperling ◽

R. Green ◽

S. Clark ◽

D. Vawdrey ◽

...

Keyword(s):

Emergency Department ◽

New York ◽

Hiv Testing ◽

Intervention Group ◽

Hiv Screening ◽

Intervention Period ◽

Post Intervention ◽

Hiv Test ◽

The Impact ◽

Post Intervention Group

SummaryObjective: Based on US. Centers for Disease Control and Prevention recommendations, New York State enacted legislation in 2010 requiring healthcare providers to offer non-targeted human immunodeficiency virus (HIV) testing to all patients aged 13–64. Three New York City adult emergency departments implemented an electronic alert that required clinicians to document whether an HIV test was offered before discharging a patient. The purpose of this study was to assess the impact of the electronic alert on HIV testing rates and diagnosis of HIV positive individuals.Methods: During the pre-intervention period (2.5–4 months), an electronic “HIV Testing” order set was available for clinicians to order a test or document a reason for not offering the test (e.g., patient is not conscious). An electronic alert was then added to enforce completion of the order set, effectively preventing ED discharge until an HIV test was offered to the patient. We analyzed data from 79,786 visits, measuring HIV testing and detection rates during the pre-intervention period and during the six months following the implementation of the alert.Results: The percentage of visits where an HIV test was performed increased from 5.4% in the pre-intervention period to 8.7% (p<0.001) after the electronic alert. After the implementation of the electronic alert, there was a 61% increase in HIV tests performed per visit. However, the percentage of patients testing positive per total patients-tested was slightly lower in the post-intervention group than the pre-intervention group (0.48% vs. 0.55%), but this was not significant. The number of patients-testing positive per total-patient visit was higher in the post-intervention group (0.04% vs. 0.03%).Conclusions: An electronic alert which enforced non-targeted screening was effective at increasing HIV testing rates but did not significantly increase the detection of persons living with HIV. The impact of this electronic alert on healthcare costs and quality of care merits further examination.Citation: Schnall R, Liu N, Sperling J, Green R, Clark S, Vawdrey D. An electronic alert for HIV screening in the emergency department increases screening but not the diagnosis of HIV. Appl Clin Inf 2014; 5: 299–312 http://dx.doi.org/10.4338/ACI-2013-09-RA-0075

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False-Positive HIV Test Results in Infancy and Management of Uninfected Children Receiving Antiretroviral Therapy

The Pediatric Infectious Disease Journal ◽

10.1097/inf.0000000000000684 ◽

2015 ◽

Vol 34 (6) ◽

pp. 607-609 ◽

Cited By ~ 9

Author(s):

Catherine G. Sutcliffe ◽

William J. Moss ◽

Philip E. Thuma

Keyword(s):

Antiretroviral Therapy ◽

False Positive ◽

Test Results ◽

Hiv Test

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Refrain from Telling Bad News: Patients with Leishmaniasis Can Have False-Positive HIV Test Results

Clinical Infectious Diseases ◽

10.1086/518709 ◽

2007 ◽

Vol 45 (1) ◽

pp. 139-140 ◽

Cited By ~ 8

Author(s):

A. Salinas ◽

M. Gorgolas ◽

M. Fernandez-Guerrero

Keyword(s):

False Positive ◽

Bad News ◽

Test Results ◽

Hiv Test

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Risk Factors Associated with False Positive HIV Test Results in a Low-Risk Urban Obstetric Population

Journal of Pregnancy ◽

10.1155/2012/841979 ◽

2012 ◽

Vol 2012 ◽

pp. 1-4 ◽

Cited By ~ 7

Author(s):

Tamara T. Chao ◽

Jeanne S. Sheffield ◽

George D. Wendel ◽

M. Qasim Ansari ◽

Donald D. McIntire ◽

...

Keyword(s):

Risk Factors ◽

False Positive ◽

Low Risk ◽

Test Results ◽

Factors Associated ◽

Hiv Test ◽

Obstetric Population

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HIV-related risk factors of blood donors in northern Thailand before and after knowing HIV test results

International Journal of Epidemiology ◽

10.1093/ije/26.2.408 ◽

1997 ◽

Vol 26 (2) ◽

pp. 408-413

Author(s):

P Sawanpanyalert ◽

W Uthaivoravit ◽

H Yanai ◽

K Limpakarnjanarat ◽

T. Mastro ◽

...

Keyword(s):

Risk Factors ◽

Blood Donors ◽

Test Results ◽

Northern Thailand ◽

Related Risk ◽

Hiv Test ◽

Before And After

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1299. Cluster of False-Positive “Fifth-Generation” HIV Test Results During Implementation of a Routine HIV Screening Program in an Emergency Department

Open Forum Infectious Diseases ◽

10.1093/ofid/ofz360.1162 ◽

2019 ◽

Vol 6 (Supplement_2) ◽

pp. S468-S468

Author(s):

Andrew B Trotter ◽

Anjana Maheswaran ◽

Mary Kate Mannion ◽

Sara Baghikar ◽

Janet Lin

Keyword(s):

Emergency Department ◽

Hiv Testing ◽

False Positive ◽

Screening Program ◽

False Positives ◽

Hiv Screening ◽

Fifth Generation ◽

Hiv Test ◽

Hiv Antigen ◽

Hiv 1

Abstract Background In November 2014, the University of Illinois Hospital (UI Health) introduced an electronic medical record (EMR)-driven HIV screening program in the emergency department (ED). In October 2016, our hospital laboratory introduced “Fifth-generation” HIV testing using the Bio-Rad BioPlex 2200 HIV Antigen/Antibody diagnostic assay. Fifth-generation HIV testing has the advantage of separately detecting and reporting HIV antibody and HIV-1 p24 antigen. Although the literature and manufacturer report high sensitivity and specificity of this test, we encountered higher than expected rates of false-positive tests during the introduction of this test. Methods We retrospectively reviewed the results of our ED HIV screening program from October 2016 to March 2019 to describe the outcomes of HIV testing, determine the rates of false-positive HIV tests and determine if false-positive rates were temporally clustered. We also investigated various potential causes of higher than expected false positives including pre-analytical and analytical error. We defined a false-positive test as a repeatedly reactive initial HIV antigen and/or HIV-1 antibody result with a subsequent negative or indeterminate HIV-1/2 antibody differentiation immunoassay and negative HIV-1 nucleic amplification test. Results During the review period, out of a total of 17,385 HIV tests which were performed, 85 tests were confirmed positive and 27 were false positives. This represents an HIV prevalence of 0.5%. Eighteen of the 27 false positives occurred during an 8 month period between October 2016 and April 2017 (see Figure 1). During our investigation of potential causes of the false-positive tests, we discovered that a reagent lot for the test was changed in June 2017 which resulted in a significant decrease in the false-positive rate (0.33% to 0.07%). Conclusion We provide data which suggests that a reagent lot may have been the cause of higher than expected false-positive tests for HIV testing. Monitoring of testing outcomes during implementation of a routine HIV testing program can help identify potential root causes of false-positive tests. Disclosures All authors: No reported disclosures.

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Centrifugation may eliminate false-positive leucocyte esterase strip test results caused by inflammatory arthritis in the diagnosis of knee infection

Bone and Joint Research ◽

10.1302/2046-3758.95.bjr-2019-0245.r1 ◽

2020 ◽

Vol 9 (5) ◽

pp. 236-241

Author(s):

Rui Li ◽

Chi Wang ◽

Xiao-Jian Ji ◽

Qing-Yuan Zheng ◽

Xiang Li ◽

...

Keyword(s):

False Positive ◽

Inflammatory Arthritis ◽

Test Results ◽

Knee Infection ◽

Negative Results ◽

Before And After ◽

Strip Test ◽

Positive Results ◽

Test Result ◽

Colour Chart

Aims The purpose of this study was to validate our hypothesis that centrifugation may eliminate false-positive leucocyte esterase (LE) strip test results caused by autoimmune diseases in the diagnosis of knee infection. Methods Between January 2016 and May 2019, 83 cases, including 33 cases of septic arthritis and 50 cases of aseptic arthritis, were enrolled in this study. To further validate our hypothesis, another 34 cases of inflammatory arthritis from the Department of Rheumatology of our institution were also included. After aspiration, one drop of synovial fluid was applied to LE strips before and after centrifugation. The results were recorded after approximately three minutes according to the different colour grades on the colour chart. The differences of LE results between each cohort were analyzed. Results Before centrifugation, 46% (23/50) of the LE strip tests in the aseptic arthritis group were false-positives. Most of the false-positive results were due to inflammatory arthritis; after centrifugation, 78.3% (18/23) of the tests yielded negative results. Similar results were observed in cases from the Department of Rheumatology. The sensitivity of the centrifuged LE strip test was 0.818 (0.639 to 0.924), which is still an acceptable level compared with the uncentrifuged results, which yielded a sensitivity of 0.909 (0.745 to 0.976). However, the specificity was increased from 0.540 (0.395 to 0.679) to 0.900 (0.774 to 0.963) after centrifugation. Conclusion Although inflammatory arthritis can yield a false-positive LE strip test result in the diagnosis of knee infection, centrifugation may eliminate these false-positive results. Cite this article: Bone Joint Res. 2020;9(5):236–241.

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