title: Fite-Faraco staining in combination with multiplex polymerase chain reaction: a new approach to leprosy diagnosis.
abstract: BACKGROUND
  Leprosy is not always an easy disease to diagnose, and patients can remain undiagnosed for longtime, not only at the peripheral clinics but also even at places with higher medical facilities, so, there is an urgent need for rapid and definitive modalities for leprosy diagnosis. This prospective study evaluates the ability of Fite-Faraco staining (FF staining) and multiplex polymerase chain reaction (PCR) over hematoxylin and eosin staining (H and E staining) and Ziehl-Neelsen staining (ZN staining).
  
  
  OBJECTIVE
  The aim of this perspective study is to evaluate the effectiveness of FF staining in combination with multiplex PCR for the early and rapid diagnosis of leprosy than any other coexisting diagnosis tool.
  
  
  METHODS
  Patients with new skin patches or nodules with or without evidence of nerve damage were selected for the study. Punch biopsy was collected according to standard procedures. Each biopsy sample was divided into two equal parts, one half was fixed in 4% (v/v) buffered neutral formalin and then accordingly embedded in paraffin. Sections were stained by three different methods: H and E staining for histopathological examination, ZN staining, and FF staining for detection of acid-fast bacilli (AFB). And the other part was subjected for DNA extraction and PCR was carried out by the obtained DNA sample.
  
  
  RESULTS
  H and E staining, ZN staining, FF staining, and PCR yield 58.2%, 50.9%, 60%, and 67.7% successful diagnosis of leprosy. The true diagnostic performances for these techniques were as follows: H and E staining - sensitivity 70.6%, positive predictive value (PPV) 81.9%, negative predictive value (NPV) 53.6%. For ZN staining - sensitivity 59.9%, PPV 69%, NPV 45.7%. For FF staining - sensitivity 74.6%, PPV 85.9%, NPV 56.7%, and for PCR - sensitivity 87.8%, PPV 95.6%, NPV 71.2%.
  
  
  CONCLUSIONS
  The combination of FF staining and PCR was shown to provide a rapid and definitive diagnosis in the majority of leprosy suspected cases with a higher positive likelihood ratio (+LR) of 7.76 and 2.716, respectively, than H and E staining of 2.244 and ZN staining of 1.378.
authors: Department of Biochemistry, Institute of Post Graduate Medical Education and Research, Kolkata, West Bengal, India.
authors: Abu Hena Hasanoor
authors: AH
authors: Reja
authors: Nibir
authors: N
authors: Biswas
authors: Supratik
authors: S
authors: Biswas
authors: Sarbani
authors: S
authors: Dasgupta
authors: Imran Hussain
authors: IH
authors: Chowdhury
authors: Surajita
authors: S
authors: Banerjee
authors: Tapas
authors: T
authors: Chakraborty
authors: Pijush Kumar
authors: PK
authors: Dutta
authors: Basudev
authors: B
authors: Bhattacharya
mesh_terms: D001706:Biopsy; D004269:DNA, Bacterial / Q000032:analysis / Q000235:genetics; D004801:Eosine Yellowish-(YS); D006416:Hematoxylin; D006801:Humans; D007918:Leprosy / Q000175:diagnosis* / Q000235:genetics* / Q000473:pathology; D008828:Microbiological Techniques; D060885:Multiplex Polymerase Chain Reaction / Q000379:methods*; D009166:Mycobacterium leprae / Q000235:genetics* / Q000302:isolation & purification*; D011446:Prospective Studies; D013194:Staining and Labeling / Q000379:methods*
chemical_list: D004269:DNA, Bacterial; D004801:Eosine Yellowish-(YS); D006416:Hematoxylin