Home > Pathology > Blood Types

Blood Types

By: Jack Claridge - Updated: 13 Dec 2016 | comments*Discuss
 
Blood Types Dna Blood A B System

The first question to ask and indeed to answer when looking into the area of blood types is: what is blood?

What is Blood?

Blood is - for the most part - the liquid part of the human body, which is called Plasma; and this Plasma contains proteins, clotting factors, electrolytes (which carry small electrical stimuli) and a varying number of cells.

These cells when broken down are:

  • Platelets: Small cells involved in the clotting process which enable the flow of blood to be kerbed if a small cut or wound is inflicted
  • Leucocytes: The blood's white cells.
  • Erythrocytes: The blood's red cells.
After a wound has been inflicted and clotting has taken place the remaining fluid - known as serum - is a discoloured yellow and is still full of proteins and enzymes - this serum as we shall discuss is useful in the forensic process.

Blood Groups and Crime

Now that we have established in a little more detail what blood actually is; it is important to look at how the different blood groups are made up and also how these blood types are used in the categorisation of suspects in crimes where blood and other bodily fluids are secreted.

Forensics use a system called the 'ABO System', which is a system that measures antigens; antigens within the body determine blood type and are normally categorised as either A or B. Antigens categorised as being Type A are found in an individual's red blood cells whilst the same equation can be applied to someone of Type B blood grouping.

Also within the blood typing system there are Rhesus antigens, which can be categorised as Type D; should an individual's red blood cells have these Rhesus antigens they are classed as RH Positive and likewise if they do not appear they are classified as RH negative (or Rhesus Negative).

At a crime scene where there has been blood spilled - either that of the victim or that of the assailant - and indeed in some instances that of both parties; a serologist will take blood samples in order to identify who's blood belongs to whom.

Taking the aforementioned factors into consideration makes this process somewhat less complex than it perhaps sounds and this blood grouping system is also used to determine from which blood group the individual's parents were categorised.

Parents may have different blood from their children and indeed siblings may also have different blood groups but through the use of DNA fingerprinting it is possible to draw up certain characteristics that are shared between the father and mother and their offspring; this is called Mitochondrial DNA and can be found all the way through a family's bloodline over many generations.

These blood types although used as a means of collating DNA evidence can be used more as a means of identification that an admission of guilt. As the discovery of a blood type through the use of a sample is useful it is not an exact enough science to prove that an individual has been the perpetrator of a crime on its own.

Other such evidence - as we have already mentioned - DNA evidence, trace evidence and eye witness accounts must all be used to compile a picture that can be used in any prosecution case.

You might also like...
Topics
Latest Comments
  • Molls
    Re: The Rate of Decay in a Corpse
    Evening, just recently i have come home only to find lots of bluebottle/house-hold flies in my bedroom. I live in the attic part…
    18 January 2017
  • Whezzy
    Re: Rigor Mortis and Lividity
    My 28 yr old son died in his sleep. Cause of death accidental overdose. There are many things that make me wonder if that is an…
    15 January 2017
  • Zai
    Re: The Rate of Decay in a Corpse
    Hi! My father died two months ago. On the 13th of November.please I would like to know how his body has become?he was embalmed in…
    13 January 2017
  • Staypretty
    Re: Determining Cause of Death
    Confused & needing answers??? My father went in for a surgery a week before Christmas 2016 to have a spot of cancer taken off his…
    12 January 2017
  • Jessica
    Re: Drowning and Forensics
    Please help, my sister, went missing on January 31 2016, we knew right away something was wrong. She had been recently married but having…
    12 January 2017
  • B&B143
    Re: Determining Cause of Death
    My 8 yr old was hit & killed while getting on Upson County School Bus( the bus 20 min early, and the bus video magically disappeared,…
    12 January 2017
  • B&B143
    Re: Determining Cause of Death
    My 8 yr old was hit & killed while getting on Upson County School Bus( the bus 20 min early, and the bus video magically disappeared,…
    12 January 2017
  • tittyboi
    Re: Estimating The Time of Death
    Rectal thermometer? Sounds like abuse to the dead. 'am I right ?
    11 January 2017
  • Staypretty
    Re: Determining Cause of Death
    Confused & needing answers??? My father went in for a surgery a week before Christmas 2016 to have a spot of cancer taken off his…
    11 January 2017
  • gbexs
    Re: Forensic Archaeology
    I am a masters student of forensic science at the university of Ibadan, Nigeria. I am at the stage of writing my thesis and i want to write…
    9 January 2017
Further Reading...
Our Most Popular...
Add to my Yahoo!
Add to Google
Stumble this
Add to Twitter
Add To Facebook
RSS feed
You should seek independent professional advice before acting upon any information on the ExploreForensics website. Please read our Disclaimer.