Immunohistochemistry: Difference between revisions

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Mikael Häggström (talk | contribs)
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Mikael Häggström (talk | contribs)
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| Actin HHF-35 || 0% || 71%
| Actin HHF-35 || 0% || 71%
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Let's say for example that your pre-test probability was about 30% for pleomorphic liposarcoma and 70% for pleomorphic rhabdomyosarcoma, that desmin stains positive, and actin HHF-35 stains negative in this case. The probability that pleomorphic liposarcoma shows these immunohistochemistry results at hand is:
Let's say for example that your pre-test probability was about 30% for pleomorphic liposarcoma and 70% for pleomorphic rhabdomyosarcoma, that desmin stains positive, and actin HHF-35 stains negative in this case. Assuming that 0% positive rate means that 100% stain negative, the probability that pleomorphic liposarcoma shows these immunohistochemistry results at hand is:
*17% x (100% - 0%) = 17%
*17% x 100% = 17%
The gross likelihood of pleomorphic liposarcoma therefore becomes:
The gross likelihood of pleomorphic liposarcoma therefore becomes:
*30% x 17% = 5.1%
*30% x 17% = 5.1%
The corresponding gross likelihood of pleomorphic rhabdomyosarcoma is calculated as:
In the same way, the corresponding gross likelihood of pleomorphic rhabdomyosarcoma is calculated as:
*70% x 95% x (100% - 71%) = 19%
*70% x 95% x (100% - 71%) = 19%
As a result in this case, immunohistochemistry resulted in pleomorphic rhabdomyosarcoma going from about twice as likely compared to pleomorphic liposarcoma to about 4 times as likely.<ref group=notes>More detailed explanations about likelihood calculations on differential diagnoses in general can be read at:<br>-{{cite journal | last=Häggström | first=Mikael | title=An epidemiology-based and a likelihood ratio-based method of differential diagnosis | journal=WikiJournal of Medicine | publisher=Wikiversity Journal of Medicine | volume=1 | issue=1 | year=2014 | issn=2002-4436 | doi=10.15347/wjm/2014.002}}</ref>
As a result in this case, immunohistochemistry resulted in pleomorphic rhabdomyosarcoma going from about twice as likely compared to pleomorphic liposarcoma to about 4 times as likely.<ref group=notes>More detailed explanations about likelihood calculations on differential diagnoses in general can be read at:<br>-{{cite journal | last=Häggström | first=Mikael | title=An epidemiology-based and a likelihood ratio-based method of differential diagnosis | journal=WikiJournal of Medicine | publisher=Wikiversity Journal of Medicine | volume=1 | issue=1 | year=2014 | issn=2002-4436 | doi=10.15347/wjm/2014.002}}</ref>
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