Preservative, Preservation & Preserved!

Preservation of Viscera

1.  Stomach and its contents

2.  30 cm small Interline and contents

3.  Liver > 500 gms                             

4.  One kidney/Half of each                            

5.  Blood 100 cc (in NaF), (Minimum 10 ml)*

• Blood Best Specimen.
• Peripheral blood concentration ( femoral ) have been shown to be more reliable for toxicological analysis than the conventional heart blood.
•  

6.  Urine > 100 cc–(in Thymol)* [Toulene* is the best preservative for urine examination]

     •    The best preservative for preservation of viscera is rectified spirit.

     •    Most commonly used preservative is saturated sodium chloride.

     •    Rectified spirit is not used in:

          –   Alcohol

          –   Phenol

          –   Phosphorous 

[ Alcohol also cannot be used in case of  phosphorus poisoning, because  alcohol prevents the luminosity of phosphorus in dark ]

          –   Paraldehyde.

     •    Formaldehyde is used for preservation of Museum specimens and not for preservation of viscera for toxicological analysis.

     •    Formalin is 40% formaldehyde.

     •    NaF should be added to urine, blood, vitreous humor for Alcohol estimation and to samples of

          –   Cocaine (C)                  

          –   Carbon monooxide (C)   ® 3C’s

          –   Cyanide (C)         

Special Preservations :

Liver is the most important tissue because it concentrates many substances.

Heart–Strychnine, Digitalis.

Spleen–It is the best organ for Cyanide poisoning. ( ? Supposedly best specimen for DNA )

Brain–Alkaloids, organophosphates, volatile organic poisons.

Bile–Narcotic drugs, cocaine, methadone, Gluta­thione, Barbiturates, Tranquilizers.Opiates and acetaminophen

Vitreous–Alcohol, Chloroform. [ Vitreous Humour is preserved by keeping at 4ºC for 48 hours, normally preservative is of no value..though could be preserved with sodium fluoride (10 mg/ml). ]

Lung–Gaseous poison, HCN, Alcohol, Chloroform.

Bone–Arsenic, Antimony, Thallium, Radium.

Skin–C/o hypodermic injections (10 cm radius about site with muscle and fat), snake bite.

Hair, Nails, Uterus, spinal card–When indicated.

CSF–(in 10 mg NaF/ml of fluid) in Alcohol intoxi­cation.

Body Fat—Endrin , DDT(Organo Chlorines).

Muscle–When internal organs badly putrified.Skeletal Muscle of Buttock best specimen for Toxicology in Embalming

•    Viscera is stored at 4°C.

•    Histopathology specimen is preserved in 10% neutral formalin/95% Alcohol.

•    Virology specimen 80% Glycerol in Buffer saline.

REFERENS

Sumit Seth ,. Review of Forensic Medicine 4 th edition