Optimal group based testing strategy for detecting infected individuals: comparison of algorithms

AbstractWe investigate group based testing strategy targeted to identify infected patients by making use of a medical test which equally well applies to single and pooled samples. We demonstrate that, under assumed setting, quick sort grounded testing algorithm allows to reduce average costs, and the reduction is very significant when the infection percentage is low. Although the basic idea of test sampling is known, our major novelty is the rigorous treatment of the model. Another interesting insight following rigorous analysis is that an average number of tests per one individual scales like entropy of the prevalence of infection. One more reason for the paper is the context: taking into account the current situation with the coronavirus, dissemination of renowned ideas and the optimisation of algorithms can be of a great importance and of economical benefit.

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Pooled Sputum for Xpert MTB/RIF Testing: A Cost Effectiveness Diagnostic Tool in Mwanza, Tanzania

10.21203/rs.3.rs-599005/v1 ◽

2021 ◽

Author(s):

Shimba Henerico ◽

Richard V. Makapa ◽

Bernard C. Okamo ◽

Benson R. Kidenya ◽

Geoffrey Japhet ◽

...

Keyword(s):

Cost Effectiveness ◽

Low Income ◽

Public Health Problem ◽

Positive Sample ◽

Low Income Countries ◽

Global Public Health ◽

Testing Strategy ◽

Pooled Testing ◽

The Individual ◽

Pooled Samples

Abstract Background: Tuberculosis (TB) is a global public health problem, with the highest burden occurring in low-income countries, wherein the use of more sensitive diagnostics, such as Xpert MTB/RIF (GeneXpert), is still limited by costs. Testing of pooled samples from various individuals has been thought and thus investigated as a cost saving strategy to diagnose some diseases including TB. Then in cases where a pool is positive, retesting of the individual samples in that pool is done to identify the positive sample. We assessed the utility of a pooled testing strategy to optimize the affordability of GeneXpert for the diagnosis of TB Mwanza Tanzania. Methods: Remainder of samples from presumptive TB patients submitted for routine TB diagnosis were used for pooled samples (5 per pool) testing. The agreement of the results between individual sample testing against pooled samples testing and cost-effectiveness were assessed.Results: A total of 250 individual routinely submitted samples for TB diagnosis were tested using the established protocols. The median age of study participants was 35 [IQR 27 – 40] years and 143 (57.2%) were males. Of the 250 samples, 28 (11.2%) were detected to have MTB whereas 222 (88.8%) samples, were negative. Of the 50 sputum pools made, MTB were detected in 17 (34.0%) pools. Following retesting of these 17 positive pools, all 28 (100%) individual MTB samples were detected with the overall agreement being 100% (With the sensitivity of 100% and specificity of 100%). The number of individual MTB positive ranged from 1 to 3 per pool. Using pooling of sputum samples, the technique saved 115 (46.0%) of the cartridges in running 250 samples. This is equivalent to saving US$ 1147.7. Conclusion: The pooled sputum testing strategy reduced cartridge costs by 46.0%. The use of the pooled testing strategy reduces costs and has the potential to increase the affordability of GeneXpert testing in countries with limited resources. Pooled sputum for Xpert MTB/RIF can be used as an affordable diagnostic and/or screening tool in resource limited settings, such as Tanzania.

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Missing two key parameters in the pooled testing strategy

10.21203/rs.3.rs-1028619/v1 ◽

2021 ◽

Author(s):

Xuhua Xia

Keyword(s):

Maximum Likelihood ◽

Maximum Likelihood Estimators ◽

Infection Prevalence ◽

Testing Strategy ◽

Significant Saving ◽

Pooled Testing ◽

Testing Strategies ◽

Testing Data ◽

Pooled Samples ◽

Time Resource

Abstract The pooled testing strategy [1] misses two key parameters, the infection prevalence p and its variance mentioned many times in the paper as the key determinants of any pooled testing strategy. For illustrating their methods, the authors used p from other studies that employed individual tests. It turned that that no statistical estimators for p and its variance have ever been derived for testing data of pooled samples since the first formulation of testing strategies based on pooled sampled in 1943 [2]. Here I derive the maximum likelihood estimators for p and its variance based on tests of pooled samples. This should result in significant saving in time, resource, and costs.

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Environmental Problems and Protection Measures on Wastewater Treatment from Hardware Tool Plant in Danzao Town

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.779-780.1557 ◽

2013 ◽

Vol 779-780 ◽

pp. 1557-1561

Author(s):

Chen Yuan Sha ◽

Guo Xin Chen ◽

Xun An Ning

Keyword(s):

Wastewater Treatment ◽

Local Development ◽

Environmental Problems ◽

Current Situation ◽

Protective Measures ◽

Protection Measures ◽

Economical Benefit ◽

Pillar Industry ◽

Hardware Industry

Hardware industry, as a traditional pillar industry in Danzao Town, has brought great economical benefit for local development. However, it brings huge economic increase as well as a series of environmental problems. The characteristics and featured pollutants of the wastewater from hardware tool plant in Danzao Town are summarized in this paper. The current situation and the environmental problems caused by hardware tool plant in Danzao Town are also elaborated. Eventually, some protective measures are given to handle the problems.

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Paper 20: The Thermodynamics of Charging and Discharging Processes

Proceedings of the Institution of Mechanical Engineers Conference Proceedings ◽

10.1243/pime_conf_1965_180_277_02 ◽

1965 ◽

Vol 180 (10) ◽

pp. 16-24 ◽

Cited By ~ 3

Author(s):

J. H. Horlock ◽

W. A. Woods

Keyword(s):

Internal Combustion Engines ◽

Entropy Change ◽

Discharge Process ◽

Combustion Engines ◽

Rigorous Analysis ◽

Temperature Relation ◽

Exchange Processes ◽

Rigorous Treatment ◽

Charging And Discharging Processes ◽

Special Case

A comprehensive analysis of charging and discharging processes is presented. The work is of particular relevance to gas exchange processes which occur in internal combustion engines. A rigorous treatment is given of discharge from and charge to a container. In the discharge process irreversibility in the container and the outlet passage are considered separately. A unique pressure-temperature relation is derived for a special case of the charging process and an equation giving the entropy change in the container is derived. It is shown that the mass trapped in the container is a linear function of the pressure in the container. The case of discharge from one container to another is considered, as is the problem of consecutive charging and discharging of one container. For simultaneous charging and discharging no entirely rigorous analysis can be derived. Two analyses—those of ‘filling and emptying’ and ‘perfect displacement’—are presented.

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Testing Pooled Sputum with Xpert MTB/RIF for Diagnosis of Pulmonary Tuberculosis To Increase Affordability in Low-Income Countries

Journal of Clinical Microbiology ◽

10.1128/jcm.00864-15 ◽

2015 ◽

Vol 53 (8) ◽

pp. 2502-2508 ◽

Cited By ~ 11

Author(s):

Saddiq T. Abdurrahman ◽

Omezikam Mbanaso ◽

Lovett Lawson ◽

Olanrewaju Oladimeji ◽

Matthew Blakiston ◽

...

Keyword(s):

Low Income ◽

Public Health Problem ◽

Low Income Countries ◽

Global Public Health ◽

Testing Strategy ◽

Content Type ◽

Pooled Testing ◽

Negative Results ◽

The Individual ◽

Pooled Samples

Tuberculosis (TB) is a global public health problem, with the highest burden occurring in low-income countries. In these countries, the use of more sensitive diagnostics, such as Xpert MTB/RIF (Xpert), is still limited by costs. A cost-saving strategy to diagnose other diseases is to pool samples from various individuals and test them with single tests. The samples in positive pool samples are then retested individually to identify the patients with the disease. We assessed a pooled testing strategy to optimize the affordability of Xpert for the diagnosis of TB. Adults with presumptive TB attending hospitals or identified by canvassing of households in Abuja, Nigeria, were asked to provide sputum for individual and pooled (4 per pool) testing. The agreement of the results of testing of individual and pooled samples and costs were assessed. A total of 738 individuals submitted samples, with 115 (16%) beingMycobacterium tuberculosispositive. Valid Xpert results for individual and pooled samples were available for 718 specimens. Of these, testing of pooled samples detected 109 (96%) of 114 individualM. tuberculosis-positive samples, with the overall agreement being 99%. Xpert semiquantitativeM. tuberculosislevels had a positive correlation with the smear grades, and the individual sample-positive/pooled sample-negative results were likely due to theM. tuberculosisconcentration being below the detection limit. The strategy reduced cartridge costs by 31%. Savings were higher with samples from individuals recruited in the community, where the proportion of positive specimens was low. The results of testing of pooled samples had a high level of agreement with the results of testing of individual samples, and use of the pooled testing strategy reduced costs and has the potential to increase the affordability of Xpert in countries with limited resources.

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