<prompt> In an oil immersion field 1-10 tubercle bacilli were seen per 10 field. It indicatesScanty  <response>: Ref: PubMed; stylefont-size: 1.04761904761905em; font-family: Times New Roman, Times, serif; margin: 0 0 0 8px; text-indent: 0 Oil immersion is a technique used to increase the resolving power of a microscope. This is achieved by immersing both the objective lens and the specimen in a transparent oil of high refractive index, thereby increasing the numerical aperture of the objective lens.Reporting the Bacterial Index The results are reported on a 0 to 6 semi-logarithmic scale using a descriptive phrase or numerical code. This is an indicator of the total bacillary load of the patient. It falls about 1 point per year during effective treatment as dead bacilli undergo lysis and are absorbed.Very numerous6Over 1000 bacilli per oil immersion fieldNumerous5100 to 1000 bacilli per oil immersion fieldModerate410 to 100 bacilli per oil immersion fieldFew31 to 10 bacilli per oil immersion fieldVery few21 to 10 bacilli per 10 fieldsRare11 to 10 bacilli per 100 fieldsNone foundNFNo AFB seen on entire site 