Table 1. Recommended incubation times for chromosomal preparations

Table


	Incubation times
Tissue	Colcemid solution (Step 7)	Hypotonic solution (Step 12)	Trypsin solution^a (Step 26)

Cultured lymphocytes	45 min	10 min	~30 sec
Amniotic fluid cells	25 min	45 min	~40 sec
Chorionic villus cells	25 min	45 min	~40 sec
Skin fibroblasts	25 min	45 min	~40 sec
Spontaneous abortion tissues	25 min	45 min	~40 sec

Bone marrow	30 min	15 min^b	~15-25 sec

^aThe amount of time needed for trypsin digestion can vary. See Troubleshooting.
^bHypotonic solution (for bone marrow cells) is designed specifically for use with bone marrow preparations and is recommended for this step.