dr. shiuli, forensic medicine & toxicology, kgmu

Dr. Shiuli, Forensic Medicine & Toxicology, KGMU

MEDICOLEGAL ASPECTS OF BLOOD AND OTHER

STAINS


Different stains having Medicolegal importance

Blood Seminal fluid Vaginal discharge Saliva Faecal stain Urine


Blood stains

-Main cellular content RBC – Haemoglobin which possess peroxidase activity-Haemoglobin and other proteins of blood has antigenic properties – produces antibodies when injected into animals


Medicolegal importance May establish a link between offence,

offended and offender May establish link between offence and

offensive agent Fictitious charges by presenting an

animal stain as human In poisoning, poison chemically

detected Time since death may be estimated by

chemical and enzymatic study


Examination

Whether the stain is actually a blood stain

• Physical• Chemical• Microscopic• Spectroscopic • Micro chemical


Whether the blood stain is of human or other than human

• Precipitin test If human, which blood group Sex, source Indication as to cause of death Whether belong to victim or accused Whether bleeding antemortem or

postmortem Any disease process


Substances resembling blood stain

Vegetable stains- ammonia greenish yellow color- Bleached by chlorine water- M/E vegetable cells and fibers Rust stains- Does not fall off in scale on being

heated- Positive reaction for iron- Dissolved in dil. Hcl


Mineral stains Synthetic dye stains- Nitric acid yellow strong alkali original color Other stains


Chemical examination Highly sensitive Positive reaction even with faint traces

of blood Principal factor – peroxidase activity

liberating nascent oxygen which leads to colour change


1. BENZIDINE TEST

stain extract ┼ benzidine ┼ 10 vol

in hydogen peroxide

glacial acetic acid

Blue colour


2. KASTLE MAYER TEST- Phenolphthalein in alkaline medium- Pink colour

3. ORTHOTOLIDINE TEST- (4% orthotolidine in ethyl alcohol)+

glacial acetic acid + H2O2 - Green colour

4. LEUCHOMALACHITE GREEN TEST- Bluish green colour5. LUMINAL TEST


Confirmatory tests for blood


Microscopic test

RBC’s- confirmatory Species Sex Disease


Microchemical test

HAEMIN CRYSTAL TEST/ TEICHMAN’S TEST

- Sod. Chloride + strain extract + glacial acetic acid

- Yellowish brown rhombic crystals of haemin

HAEMOCHROMOGEN CRYSTAL/ TAKAYAMA TEST

- takayama reagent + stain extract- Salmon pink hemochromogen crystals


Spectroscopic examination

Detects blood where RBC structure is lost and hemoglobin has undergone chemical composition


Species specification test

PRECIPITIN TEST- When human serum is injected in an

experimental animal, antibodies develop.

- When any human serum is brought in contact with this animal serum, the antibodies and protein will react and a visible precipitate will develop


Identifying sex from blood stain- Barr bodies in > 3% of polymorphs- Y chromosome is fluorescent to quinacrine


Individuality by blood stain

Blood grouping• red cell antigen•White cell antigen•Se protein polymorphism•Red cell enzyme polymorphism


Red cell antigen ABO system Rh system MNSs group system Lutheran Duffy Lewis Kidd


Gro

up

sp

ecifi

c

su

bsta

nces

secre

tors

Non

secre

tors

Agglutinogens in water soluble form Secrete ABO antigens into body fluids

and secretions

Agglutinogens in lipoidal form


White cell antigen

Human Leucocyte Antigen (HLA)- the MHC in humans

Present on Chromosome 6 and encode cell surface antigen presenting proteins

4 types – HLA-A, HLA-B, HLA-C, HLA-D


Serum protein polymorphism

Occurrence in the same population of two or more alleles at one locus, each with appreciable frequency, where the minimum frequency is taken as 1%

Se. proteins subject to genetic variation are

• Se. haptoglobins• Se lipoproteins• Abnormal haemoglobins


Red cell enzyme polymorphism

> 250 proteins & enzymes found in red cell

Established value in paternity testing• Phopho glucomutase• Adenylate kinase

dr. shiuli, forensic medicine & toxicology, kgmu

Documents

forensic medicine toxicology

blood groupsex

proteins of blood

animal stain

kgmudifferent stains

animal serum

humanprecipitin testif

experimental animal