Traditional clinical parasitology is based upon the diagnostic combination
of two procedures: the concentration and the permanent smear. 
Historically these two procedures have required  the use of two 
separate fixatives: a heavy metal PVA for the permanent smear and 
formalin for the concentration.

Although utilized for concentration procedures, formalin distorts protozoan 
trophozoites and juvenile nematodes. LV-PVA contains mercuric chloride; it 
is extremely toxic and environmentally hazardous.  The viscosity of any PVA-
based fixative prevents concentration and direct LCA and EIA procedures.  
PVAs containing other heavy metals (zinc & copper) have similar problems 
and do not provide staining results comparable to LV-PVA or Proto-fix™ CLR.  

Until now, products attempting to overcome these limitations have been 
partially effective at best.  Alpha-Tec Systems has set the new standard in 
parasitology with Proto-fix™ CLR.