Field trial of applicability of lot quality assurance sampling survey method for rapid assessment of prevalence of active trachoma
OBJECTIVE: To test the applicability of lot quality assurance sampling (LQAS) for the rapid assessment of the prevalence of active trachoma. METHODS: Prevalence of active trachoma in six communities was found by examining all children aged 2-5 years. Trial surveys were conducted in these communities...
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| Format: | Article |
| Language: | English |
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The World Health Organization
2003-01-01
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| Series: | Bulletin of the World Health Organization |
| Subjects: | |
| Online Access: | http://www.scielosp.org/scielo.php?script=sci_arttext&pid=S0042-96862003001200006 |
| _version_ | 1797282177071710208 |
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| author | Myatt Mark Limburg Hans Minassian Darwin Katyola Damson |
| author_facet | Myatt Mark Limburg Hans Minassian Darwin Katyola Damson |
| author_sort | Myatt Mark |
| collection | DOAJ |
| description | OBJECTIVE: To test the applicability of lot quality assurance sampling (LQAS) for the rapid assessment of the prevalence of active trachoma. METHODS: Prevalence of active trachoma in six communities was found by examining all children aged 2-5 years. Trial surveys were conducted in these communities. A sampling plan appropriate for classifying communities with prevalences <20% and >40% was applied to the survey data. Operating characteristic and average sample number curves were plotted, and screening test indices were calculated. The ability of LQAS to provide a three-class classification system was investigated. FINDINGS: Ninety-six trial surveys were conducted. All communities with prevalences <20% and >40% were identified correctly. The method discriminated between communities with prevalences <30% and >30%, with sensitivity of 98% (95% confidence interval (CI) = 88.2-99.9%), specificity of 84.4% (CI = 69.9-93.0%), positive predictive value of 87.7% (CI = 75.7-94.5%), negative predictive value of 97.4% (CI = 84.9-99.9%), and accuracy of 91.7% (CI = 83.8-96.1%). Agreement between the three prevalence classes and survey classifications was 84.4% (CI = 75.2-90.7%). The time needed to complete the surveys was consistent with the need to complete a survey in one day. CONCLUSION: Lot quality assurance sampling provides a method of classifying communities according to the prevalence of active trachoma. It merits serious consideration as a replacement for the assessment of the prevalence of active trachoma with the currently used trachoma rapid assessment method. It may be extended to provide a multi-class classification method. |
| first_indexed | 2024-03-07T17:09:14Z |
| format | Article |
| id | doaj.art-d6a054306e134c689f5d179b6afd5146 |
| institution | Directory Open Access Journal |
| issn | 0042-9686 |
| language | English |
| last_indexed | 2024-03-07T17:09:14Z |
| publishDate | 2003-01-01 |
| publisher | The World Health Organization |
| record_format | Article |
| series | Bulletin of the World Health Organization |
| spelling | doaj.art-d6a054306e134c689f5d179b6afd51462024-03-03T02:18:53ZengThe World Health OrganizationBulletin of the World Health Organization0042-96862003-01-018112877885Field trial of applicability of lot quality assurance sampling survey method for rapid assessment of prevalence of active trachomaMyatt MarkLimburg HansMinassian DarwinKatyola DamsonOBJECTIVE: To test the applicability of lot quality assurance sampling (LQAS) for the rapid assessment of the prevalence of active trachoma. METHODS: Prevalence of active trachoma in six communities was found by examining all children aged 2-5 years. Trial surveys were conducted in these communities. A sampling plan appropriate for classifying communities with prevalences <20% and >40% was applied to the survey data. Operating characteristic and average sample number curves were plotted, and screening test indices were calculated. The ability of LQAS to provide a three-class classification system was investigated. FINDINGS: Ninety-six trial surveys were conducted. All communities with prevalences <20% and >40% were identified correctly. The method discriminated between communities with prevalences <30% and >30%, with sensitivity of 98% (95% confidence interval (CI) = 88.2-99.9%), specificity of 84.4% (CI = 69.9-93.0%), positive predictive value of 87.7% (CI = 75.7-94.5%), negative predictive value of 97.4% (CI = 84.9-99.9%), and accuracy of 91.7% (CI = 83.8-96.1%). Agreement between the three prevalence classes and survey classifications was 84.4% (CI = 75.2-90.7%). The time needed to complete the surveys was consistent with the need to complete a survey in one day. CONCLUSION: Lot quality assurance sampling provides a method of classifying communities according to the prevalence of active trachoma. It merits serious consideration as a replacement for the assessment of the prevalence of active trachoma with the currently used trachoma rapid assessment method. It may be extended to provide a multi-class classification method.http://www.scielosp.org/scielo.php?script=sci_arttext&pid=S0042-96862003001200006Trachoma/epidemiologyPrevalenceQuality assuranceHealth careSampling studiesValidation studiesHealth surveysCnfidence intervalsSensitivity and specificityPredictive value of testsMalawi |
| spellingShingle | Myatt Mark Limburg Hans Minassian Darwin Katyola Damson Field trial of applicability of lot quality assurance sampling survey method for rapid assessment of prevalence of active trachoma Bulletin of the World Health Organization Trachoma/epidemiology Prevalence Quality assurance Health care Sampling studies Validation studies Health surveys Cnfidence intervals Sensitivity and specificity Predictive value of tests Malawi |
| title | Field trial of applicability of lot quality assurance sampling survey method for rapid assessment of prevalence of active trachoma |
| title_full | Field trial of applicability of lot quality assurance sampling survey method for rapid assessment of prevalence of active trachoma |
| title_fullStr | Field trial of applicability of lot quality assurance sampling survey method for rapid assessment of prevalence of active trachoma |
| title_full_unstemmed | Field trial of applicability of lot quality assurance sampling survey method for rapid assessment of prevalence of active trachoma |
| title_short | Field trial of applicability of lot quality assurance sampling survey method for rapid assessment of prevalence of active trachoma |
| title_sort | field trial of applicability of lot quality assurance sampling survey method for rapid assessment of prevalence of active trachoma |
| topic | Trachoma/epidemiology Prevalence Quality assurance Health care Sampling studies Validation studies Health surveys Cnfidence intervals Sensitivity and specificity Predictive value of tests Malawi |
| url | http://www.scielosp.org/scielo.php?script=sci_arttext&pid=S0042-96862003001200006 |
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