Preservation of Viscera in Suspected Poisoning Cases

When to Preserve Viscera

1. Death is suspected to be due to poisoning (by police or doctor)
2. Deceased was intoxicated or known to use drugs
3. Cause of death not found even after full autopsy
4. Unusual smell, color, or unidentifiable material detected in stomach contents
5. Anaphylactic deaths
6. Deaths due to burns
7. Advanced decomposition
8. Accidental death involving a driver of a vehicle or machine operator
9. When the investigating officer requests it
10. When medical officer suspects poison by smell or other findings during an injury autopsy

Routine Viscera - Must Be Preserved in All Suspected Cases

Note: GI tract contents must be kept in separate bottles from solid viscera, because the relative amounts of poison in stomach vs. intestine vs. solid organs give information about time since ingestion.

Containers

• Use 1-litre capacity, clean, wide-mouthed, white glass bottles with glass stoppers
• Rubber inserts under caps must NOT be used - they extract certain poisons (chloroform, phenols)
• Clean glass containers with sulphuric acid-chromate solution, rinse with distilled water, and dry
• Polyethylene bags/containers can be used, but volatile poisons may diffuse through plastic
• For lungs or tissues to be analyzed for volatile substances, use nylon bags (impermeable to such substances)
• Blood must be collected in screw-capped bottles of ~30 mL

Preservatives

(A) Saturated Common Salt (NaCl) Solution

• Used in all cases of suspected poisoning
• Exceptions - NOT used in poisoning by:
  • Corrosive acids (except phenol/carbolic acid)
  • Corrosive alkalis
  • Corrosive sublimate (mercuric chloride)
  • Aconite

(B) Rectified Spirit (Alcohol)

• Used when saturated salt is contraindicated (corrosive acid cases, except carbolic acid)
• NOT used in suspected poisoning by:
  • Alcohol, kerosene
  • Chloroform, ether
  • Chloral hydrate
  • Formic acid, formaldehyde, acetic acid
  • Phenol
  • Phosphorus (diminishes phosphorescence)
  • Paraldehyde (organic acids and paraldehyde are soluble in alcohol)

(C) Blood Preservatives (special rules)

• Routine: 10 mg/mL sodium or potassium fluoride (inhibits glycolysis, enzyme enolase, and bacterial growth) + 3 mg potassium oxalate (anti-coagulant) per 10 mL blood
• Fluoride should also be added to urine, CSF, and vitreous humor if alcohol estimation is required, and also for cocaine, cyanide, and CO analysis
• Oxalic acid / ethylene glycol / fluoride poisoning: Use 30 mg sodium citrate instead of potassium oxalate
• CO and CN poisoning: Use airtight caps; add a layer of liquid paraffin (1-2 cm) over blood to prevent exposure to atmospheric oxygen
• Do NOT use heparin or EDTA - they interfere with detection of methanol

(D) Urine Preservatives

• 1 mL concentrated HCl, or 100 mg thymol, or 100 mg sodium fluoride per 10 mL urine
• Alternatively: equal quantity of saturated NaCl or rectified spirit; or toluene (preferred)

(E) When Preservative is NOT Necessary

1. Viscera can be analyzed within 24 hours
2. Sample can be kept in a refrigerator or ice box
3. Bones, hair, nails
4. Lungs for detecting inhaled poisons

Important: Viscera must NOT be preserved in formaldehyde - extraction of poison (especially non-volatile organic compounds) becomes very difficult.

Additional Viscera in Specific Poisonings

Instructions for Packing and Dispatch

1. Separate bottles: Stomach + small intestine (one bottle); liver + kidney (second bottle); blood separately; urine separately; brain in its own bottle
2. Processing: Stomach and intestines are opened before preservation. Liver and kidney are cut into 0.5-1 cm pieces or minced
3. Quantity of preservative should be equal to or more than the viscera in bulk
4. Fill only two-thirds of bottle capacity - to avoid bursting from gases of decomposition
5. Sealing: Stoppers well-fitted, covered with cloth, tied with tape/string, ends sealed; seal as soon as possible to prevent loss of volatile substances
6. Labelling - each bottle must carry:
   • Name, age, sex of victim
   • Autopsy number
   • Police station and crime number
   • Organs contained
   • Date and place of autopsy
   • Preservative used
   • Signature of the doctor
   • Infection warning (if contents are infectious, e.g., HIV, HBV, TB, anthrax)
7. Preservative sample: 25 mL rectified spirit or 25 g NaCl separately bottled and sent - to exclude the preservative itself as a contaminant
8. Secured transport: Sealed bottles placed in a locked, sealed box with personal/departmental seal; sample seal and signature in a separate sealed envelope
9. Documentation: Copies of inquest report, PM report, and Magistrate's authorization sent to FSL along with viscera
10. Authorization: Viscera not analyzed without written authorization from a Magistrate, or a police officer not below the rank of Deputy Superintendent
11. Chain of custody: Viscera box handed to police constable with receipt; constable delivers it personally to FSL and obtains a receipt

Why Each Organ is Preserved - Rationale

• Stomach/GI: Most poisons are ingested; highest initial concentration; helps estimate quantity and time of ingestion
• Liver: Concentrates absorbed poisons even when blood levels have declined; major metabolic organ
• Kidney: Organ of excretion; contains large amounts of poison being cleared
• Blood: Reflects systemic levels; must be from peripheral vein (central blood levels may show postmortem redistribution)
• Urine: Proof of absorption and excretion; cannot be added with evil intent as it comes from the body
• Muscle: Drug levels in muscle more accurately reflect blood levels than liver or kidney

Postmortem note: After death, cellular barriers of mucous and serous membranes break down, so substances in the GI tract can migrate to thoracic and abdominal organs - causing a false rise in apparent blood levels. This is why separate bottling of GI contents vs. solid viscera is essential.

Numbered Bottle System for Viscera Preservation

As described in FMT Reddy (The Essentials of Forensic Medicine and Toxicology, 36th Ed.)

Bottle No. 1

• Stomach and intestines are opened before being placed in the bottle
• Preservative: Saturated common salt (NaCl) solution

Bottle No. 2

• Cut into pieces of 0.5-1 cm thickness, or minced in a grinder
• Preservative: Saturated common salt (NaCl) solution

Bottle No. 3

• Preservative: 10 mg/mL sodium fluoride (inhibits glycolysis, enzyme enolase, bacterial growth) + 3 mg potassium oxalate (anticoagulant) per 10 mL blood
• Use screw-capped bottle (~30 mL)

Bottle No. 4

• Preservative: 1 mL concentrated HCl, or 100 mg thymol, or 100 mg sodium fluoride per 10 mL; or equal quantity saturated NaCl or rectified spirit; Toluene is preferred

Bottle No. 5 (Control/Blank)

• Sent separately to exclude the possibility of any poison present in the preservative itself as a contaminant

Additional Bottles (Poison-Specific)

Key Rules for All Bottles (Reddy)

1. Preservative quantity must equal or exceed the bulk of viscera
2. Fill only two-thirds of bottle capacity - space for decomposition gases
3. Stopper: Well-fitted, covered with cloth, tied with tape, ends sealed; seal immediately to prevent loss of volatile substances
4. Label must contain: name, age, sex; autopsy number; police station; crime number; organs contained; date and place of autopsy; preservative used; doctor's signature; infection warning if applicable
5. Do NOT use formaldehyde - makes extraction of poisons (especially non-volatile organics) very difficult
6. Do NOT use rubber inserts under caps - extract chloroform and phenols
7. Sealed bottles placed in a locked, sealed box with personal/departmental seal; sample seal + signature in a separate sealed envelope
8. Copies of inquest report, PM report, and Magistrate's authorization sent to FSL with the viscera
9. Analysis is done only with authorization from a Magistrate or a police officer not below the rank of Deputy Superintendent
10. Viscera box handed to police constable with receipt; constable delivers to FSL personally and obtains a receipt

Preservative Exceptions - Quick Summary

• The Essentials of Forensic Medicine and Toxicology, 36th Edition (Reddy), pp. 131-132