Is pepsin treatment only required on late gestational age prenatal specimens?
Pepsin treatment always improves FISH results, regardless of cell type used – lymphocytes, bone marrow, amniocytes, sputum, etc. Cytocell does not usually recommend pepsin treatment for every product because it is time consuming and requires additional costly reagents and for ‘regular’ cytogenetics preparations the benefits do not warrant the extra work. We especially suggest that pepsin treatment be used for late gestational age samples because we have noticed that the improvement is marked and certainly worth the additional effort. This does not mean that pre-treatment is essential or only required for late gestational samples, however it can be beneficial as some people find it difficult to analyse FISH results without pre-treatment. If you already routinely perform pepsin digestion for all samples then maintain this practice as it will produce the best results.
