Forensic Medicine

[Michin Khel]

Jamiat notes are derived from naseeb awan's book. parik i think is very good for general study of forensic medicine.

[Saifullah]

Yea, parikh i find it like a bit too lengthy

[Michin Khel]

Have you consulted shahbaz's forensic medicine?, it is very good book.

[Saifullah]

Yea i will everyday, coz im revising it at the moment

[Saifullah]

OK im gonna start my revision soon...i think ill start with Blood examination

[Sheenka]

http://www.s-cool.co.uk/
this is gd site

[Saifullah]

but this site is for a level and gcse revision

[Saifullah]

Blood examination

Chemical Examination

This consists of the following

1)Presumptive or colour test
2)Cofirmatory or Microchemical test
3)Spectroscopic Examination
4)Serological examination

Ok lets explain what presumptive or colour test is about
In these tests if it is positive then it can mean blood is present but it can be positive with other human secretions. But if it is negative then we know blood is not present

Benzidine test-Positive when greenish blue colour appears
Phenolphthalein test or kastle meyer test-Positive when pink colour appears
Guaiacum Test-Positive when deep blue colour appears
Amidopyridine test-Positive when purple colour appears

This is a quick explanation of the tests for presumptive/colour test...

Next we will mention the other chemical test which is the microchemical tests which will confirm the presence of blood. Which the above tests are not confirmatory

[Saifullah]

Confirmatory test/Microchemical tests

There are two tests under this, which is

Haemochromogen crystal test or Takayamas test
and
Haemin Crystal test or Teichmanns test

In these tests reagents are added to it and then a slide is prepared and it is seen under the microscope. You can then identify the presence of blood.

[Sheenka]

i dont get wat u mean blood is present if positive ?

[Saifullah]

You have to understand that so far these blood tests do not confirm whether the blood is from a human or an animal....Microscopic examination you can tell maybe but still you then use serological testing to confirm source of blood

Serological examination
Precipitin test:

This test is performed using the three techniques....

1)Test tube technique
2)Gel diffusion technique
3)Cross over electrophoresis

This precipitin test uses serum of an animal and if mixed with human blood, then precipitins are formed (precipitins are antibodies)..then it will cause precipitate with human blood

[Saifullah]

Sheenkay like you know you do a test, then some colour change happens with the chemicals in the test. Lets say for example you mix blood with some chemical...then the chemical changes colour say for example black. So they say this is a positive reaction when it goes black, which means blood is present

[Saifullah]

Like the same happens in a titration between an acid and alkali. You wanna find the end point using some indicator.

[Sheenka]

ya sure

[Saifullah]

The other serological test is called Haem Agglutination inhibition test

its a long procedure but anyways it is used to determine human/ape blood from other animals

Latex test
A positive reaction shows clumps (agglutination). If positive it confirms presence of HUMAN blood and is specific for human blood only. And only takes 5 minutes