Comparison between 10% Buffered Formalin and Carnoy's Fluid as Routine Fixative in Histotechnology Laboratories

Abstract

This is a comparative descriptive study to compare between 10% Buffered Formalin and Carnoy’s fixative measuring their effects on the qualities of subsequent procedures such as tissues sectioning and staining. The study conducted in Khartoum during the period from 10 th November 2008 to 21st April 2009. Fifty histological specimens collected from a rabbit after anesthesia by chloroform. Tissues obtained from different organs including spleen, liver, kidneys, skin, small intestine, muscles, large intestine and cartilages . All histological specimens were fixed in wide suitable containers ten times the volume of specimen 25 of them by 10% Buffered Formalin and the other by Carnoy's fluid. Then specimens were processed, sectioned and stained by Haemtoxylin and Eosin (H and E), Periodic acid schiff's (PAS), Alcian blue and Perl’s Prussian blue, then examined microscopically. Data entered a computer, checked, verified and analyzed using SPSS program. Means were used for comparison of results. The study showed that 10% buffered formalin is the superior in section cutting, staining by H and E, staining by Alcian blue and staining by Perl's Prussian blue as (4.76), (5.28), (4.76) and (5.64) respectively, while carnoy’s represent(3.84), (4.00), (2.88) and (3.92) respectively. In staining by periodic acid Schiff’s (PAS) carnoy’s is better (4.52) followed by 10% buffered formalin (3.76). The study showed that, though Carnoy’s fixative can rapidly penetrates the tissues, but it cannot be a substitute for Buffered Formalin. Though, Formalin has credited the best results, but it might not be suitable with tissues requiring faster penetration rates such as glycogen and other important carbohydrates. Similar studies are recommended for further optimization of more save histological fixatives, Ten percent Buffered Formalin should be used as a reference for histological appearance.