title: External quality assessment for acid fast bacilli smear microscopy in eastern part of Ethiopia.
abstract: BACKGROUND
  External quality assessment (EQA) of sputum smear microscopy is essential and indispensable component of any tuberculosis program. This study assessed the EQA of acid fast bacilli (AFB) smear microscopy through onsite evaluation, blinded rechecking and panel test. A one year study was conducted on eight health institution laboratories from December 2011 to December 2012. Onsite evaluation, blinded rechecking and panel tests were used to collect data. Data were analyzed using SPSS version 16. Sensitivity, specificity, predictive values, and proportions of false readings were calculated. The level of agreement was measured using Kappa (κ) value.
  
  
  RESULTS
  Problems observed during onsite evaluation include shortages of materials, disinfectant, and poor storage and working condition. A total of 578 slides were collected for blinded rechecking, of which 102 (17.6%) were reported as positive by peripheral laboratories. The panel test revealed an overall error of 17 (25.25%) of which 14 (17.5%) were minor errors [low false negative 6 (7.5%) and low false positive 8 (10%)], and 3 (3.75%) were major errors (high false positive). The sensitivity, specificity, positive predictive values (PPV) and negative predictive values (NPV) of the peripheral laboratories were 83.5, 97.8, 91.7, and 95.7, respectively. The false readings at the peripheral laboratories were 32 (5.5%). Agreement on reading the slides was observed on 546 (94.5%) slides (K = 0.84, SE = 0.054).
  
  
  CONCLUSIONS
  Lack of reagents, supplies, favorable working environment and AFB related technical problems were identified in the peripheral laboratories. High false negative error was found to be the predominant major error. A continuous and strong EQA scheme should be implemented to avoid reporting errors and produce quality sputum results.
authors.affiliation: Department of Medical Laboratory Science, College of Health and Medical Sciences, Haramaya University, East Harerge, Ethiopia. desadmassu@gmail.com.
authors.forename: Desalegn Admassu
authors.initials: DA
authors.lastname: Ayana
authors.affiliation: Department of Medical Laboratory Science, College of Health and Medical Sciences, Haramaya University, East Harerge, Ethiopia. zelalemtmariam@yahoo.com.
authors.forename: Zelalem Teklemariam
authors.initials: ZT
authors.lastname: Kidanemariam
authors.affiliation: Department of Medical Laboratory Science, College of Health and Medical Sciences, Haramaya University, East Harerge, Ethiopia. habtemit@gmail.com.
authors.forename: Habtamu Mitiku
authors.initials: HM
authors.lastname: Tesfaye
authors.affiliation: Department of Medical Laboratory Science, College of Health and Medical Sciences, Haramaya University, East Harerge, Ethiopia. fwmlab2000@gmail.com.
authors.forename: Fitsum Weldegebreal
authors.initials: FW
authors.lastname: Milashu
mesh_terms: D005002:Ethiopia; D005188:False Negative Reactions; D005189:False Positive Reactions; D006651:Histocytochemistry / Q000379:methods / Q000592:standards*; D006801:Humans; D007202:Indicators and Reagents / Q000600:supply & distribution; D007755:Laboratories, Hospital; D008853:Microscopy; D009169:Mycobacterium tuberculosis / Q000166:cytology / Q000302:isolation & purification*; D011786:Quality Control; D012680:Sensitivity and Specificity; D013183:Sputum / Q000382:microbiology*; D013194:Staining and Labeling / Q000379:methods / Q000592:standards*; D014397:Tuberculosis, Pulmonary / Q000175:diagnosis* / Q000382:microbiology
chemical_list: D007202:Indicators and Reagents