What are the differences between FISH and ISH?

Basis of differentiation

FISH

ISH

Definition

Is a technique which uses fluorescently labeled nucleic acid probes to bind to specific target sequences within cells or tissue samples

In situ hybridization involves using a non-fluorescent hapten labeled strand of DNA, RNA, or modified nucleic acids to detect sequences within intact cells or preserved tissue sections

Use of fluorescent probes

Uses fluorescent probes

Does not involve fluorescent probes

Sensitivity 

High sensitivity due to fluorescent detection

Is comparatively less sensitive

Speed

Rapid visualization of results

Takes comparatively longer than FISH due to extra steps  

Multiplexing

Capable of multiplexing with different fluorophores

Exhibits less multiplexing capability, typically single color detection

Detection method

Fluorescent microscopy

Autoradiography or immunohistochemistry