DDx poor chromosome spreading

· Ethidum bromide making chromosomes sticky and hard to spread

· try increasing Colcemid concentration

· Cell suspension is too cellular

· Excess blood in cultures

· Slide dropping technique:

· Height of slide dropping too low

· Slide dropping conditions:

· Humidity too low

· Temperature too high

· Slide not clean prior to dropping

· Hypotonic made up incorrectly or wrong timing – too much or too little

· Fix washes – too few

· Acetic acid concentration of fix – too low

References:

· Barch MJ, Knutsen T, Spurbeck JL. The AGT Cytogenetics Laboratory Manual. 3rd ed. Lippincott Williams & Wilkins; 1997.