Serology Flashcards
1
Q
What are presumptive tests?
A
- Tests used to indicate the presence of blood, semen and saliva
- Highly sensitive to but not specific for particular substances
E.g. a colour test may indicate a stain is blood but not what kind of blood
2
Q
What are confirmatory tests?
A
- Tests positive for the substance in question and only that substance
3
Q
What are the three types of cells in blood?
A
Erythrocytes, leukocytes and platelets
4
Q
What are the presumptive tests for blood?
A
- React with the haemoglobin present in blood
- Catalytic colour tests: kastle-meyer (phenolphatelin) colour test a positive reaction will turn a deep pink and leuchomalchite green colour test will turn a positive reaction a blue/green colour
- Chemical spray/light testing: luminol -> used on large areas where blood is suspected of being cleaned up and flurescein -> similar but thicker than luminol
5
Q
What is the confirmatory test for blood?
A
- Takayama test -> if blood is present salmon coloured crystals form, very sensitive test and old blood stains may give a positive reaction
- Laboratories today do not conduct confirmatory tests for blood -> if sample is presumptive then it will be sent to the DNA unit
6
Q
What is the presumptive test for semen?
A
Acid phosphate testing -> will produce a purple colour, if no reaction occurs within 2 minutes test is negatie
7
Q
What is the confirmatory test for semen?
A
Carried out by microscopy
