Evaluation of an immunohistochemical test with polyclonal antibodies raised against mycobacteria used in formalin-fixed tissue compared with mycobacterial specific culture.
An immunohistochemical (IH) test (commercially available polyclonal antiserum rabbit anti-Myco-bacterium bovis; DAKO A/S) was used to detect the presence of mycobacteria in 65 formalin-fixed, paraffin-embedded tissue blocks from different organs, showing necrotizing caseous granuloma lesions on hematoxylin and eosin sections from 65 patients. These 65 samples were dyed using an acid-fast fluorescent technique and compared using the immunohistochemical method. Both results were also compared with the mycobacterial cultures. The IH test, compared with the culture, showed a sensitivity (S) of 52%, a specificity (Sp) of 76%, a positive predictive value (PV pos) of 61% and a negative predictive value (PV neg) of 69%. We analyze these data and discuss the possible causes of false-positive and -negative results of the IH test. This rapid test on paraffin embedded tissue seems valuable in the period when waiting for the culture results.
Carabias
E
E
Department of Pathology, University Hospital, Doce de Octubre, Madrid, Spain.
Palenque
E
E
Serrano
R
R
Aguado
J M
JM
Ballestín
C
C
D000818:Animals; D005557:Formaldehyde; D006801:Humans; D007150:Immunohistochemistry; D009161:Mycobacterium / Q000276:immunology / Q000302:isolation & purification*; D011817:Rabbits; D016707:Tissue Fixation
D005557:Formaldehyde