Toxicology sampling

1. S A M P L E
T E C H N I Q U E ( C O L L E C
T I O N ,
P R E S E R VAT I O N A N D
D I S PAT C H O F
S P E C I M E N
A N D V I S C E R A )
D R L E M A S H I N W A R I

2. L E A R N I N G
O B J E C T I V E S
• By the end of lecture students will be know
• How the specimen are collected ?
• What are the different types of specimen collected
?
• How different specimen are preserved ?
• How are they dispatched ?
• What necessary documentation to be done ?

3. I N T R O D U C T I O N
• Many specimen and samples are obtained during
an autopsy as a routine depending , on the nature
of the case.
• Post mortem examination is most probably the
single opportunity for a medico legal doctor to
obtain any type of specimen.
• It is wise to obtain as much sample in as much
details as possible and discard them later if not
required.
• In general, the specimen recovered may be
designed for several distinct purposes.

4. I N T R O D U C T I O N
• In Pakistan, Unfortunately we do not have
sophisticated crime detection laboratories or
arrangements for the minute forensic serology,
biology or other examination of the sample
• Therefore, generally little attention is paid to these
vital aspect of crime investigation

5. T Y P E S O F
S P E C I M E N S
• SPECIMENS FOR CRIME
DETECTION LABORATORY
• SPECIMEN
FOR SEROLOGY/BIOLOGICAL EXAMINATION
• SPECIMEN
FOR HISTOPATHOLOGICAL EXAMINATION
• SPECIMEN FOR TOXICLOGICAL EXAMINATION

6. S P E C I M E N S F O R
C R I M E D E T E C T I O N
L A B O R AT O R Y
• Clothing
• Sample of different types of hair
• Clippings of finger nails
• Combing the pubic hair in sexual assaults cases
• Sample of foreign materials recovered from
outside or inside of body
• Tracing of pattern of injuries

7. S P E C I M E N F O R
S E R O L O G Y / B I O L O G I C
A L E X A M I N A T I O N
• In sexual assault cases, perineal, vaginal or oral
swabs
• Samples of clotted blood from victim for ABO or
Rh grouping

8. S P E C I M E N F O R
H I S T O P A T H O L O G I C A L
E X A M I N A T I O N
• They are not a routine in medicolegal autopsy.
• However, they are taken to diagnose the
responsible or contributing disease process (e.g.
Acute myocardial infraction, brain hemorrhage ) in
sudden unsuspected deaths.
• To confirm, it is in doubt, ante mortem or post
mortem nature of the injury
• To estimate the age of some injuries or lesions
• To document the presence of foreign material
deep inside a tissue e.g. pigmentation in close
contact firearm injury
This Photo by Unknown author is licensed under CC BY-SA.

9. S P E C I M E N
F O R T O X I C O L O G I C
A L E X A M I N AT I O N
• In some cases, it may be necessary to exclude or
confirm a poison as the cause of death.
• The doctor has to collect suitable samples for
analysis, and to interpret their results in the light of
autopsy findings and the circumstances of the
death.
• It should be remembered that it is the doctor,
rather then the forensic toxicologist who has to
provide the FINAL OPINION as to the cause of
death. This Photo by Unknown author is licensed under CC BY.

10. C O L L E C T I O N
O F S P E C I M E N /
V I S C E R A
1. Blood
2. Urine
3. CSF
4. Bile

11. C O L L E C T I O N O F
S P E C I M E N /
V I S C E R A
5. Vetreous
6. Stomach and its content
7. Bone and bone marrow
8. Hairs
9. Nails and skin

12. 1 . B L O O D
• Around 25-30 ml of blood is collected and
preserved
• it should be collected in a bottle, preferably from a
peripheral site, such as vessels of the neck, arm
or leg.
• Blood should never be taken from cavities after
evisceration, as it will be contaminated from other
body fluids.
• It is also preferable not to collect blood from the
heart except in CO poisoning.

13. 2 . U R I N E
• Urine is obtained by a catheter of a supra
pubic puncture before autopsy or by
puncture of the bladder after evisceration.
• Around 100-200 ml is collected. If less,
then collect the whole quantity

14. 3 . C S F
• Cerebrospinal fluid is generally not required for
toxicological purposes.
• If required, it is obtained by cisternal or lumbar
puncture, puncture of the lateral ventricles or
aspiration from the base of the brain after
reflecting the frontal lobes.
• Collect as much fluid as possible.
• If a drug is injected Intravenously after death, it will
not cross the blood brain barrier

15. 4 . B I L E
• It is directly collected from the gall bladder, as it is too
thick to be aspirated by a syringe.
• It is helpful in morphine and chlorpromazine poisoning.

16. 5 . V I T R E O U S
• A fine hypodermic needle attached to a 5ml
syringe is inserted into the outer canthus of the
globe after pulling the eyelids aside.
• the needle is inserted in the centre of the globe
and as much vitreous is aspirated from both eyes.
• Water is injected with the same syringe to restore
the shape of the eyeball.

17. 6 . S T O M A C H
A N D C O N T E N T
• Stomach contents are collected directly
into a wide mouthed bottle.
• The exterior of the stomach is washed
and the greater curvature is opened with
large scissors
• .Then the interior is exposed to see any
capsules, tablets, etc and preserved
separately.

18. 7 . B O N E A N D B O N E
M A R R O W
• About 200gms of bone should be collected.
• It is convenient to remove about 10-15cms of the
shaft of the femur.
• Bone marrow is obtained from the sternum, femur
or vertebrae.
This Photo by Unknown author is licensed under CC BY-SA-NC.

19. 8 . H A I R S
• An adequate sample of around 10 gms of head
and pubic hairs should be removed by plucking
out, complete with roots, and not by cutting and
preserved in separate containers

20. 9 . N A I L S
A N D S K I N
• All the nails should be removed entire, from their bed
and collected in separate envelopes.
• A skin piece of at least 2.5cms square from the affected
area in case of corrosive poisoning and from thigh or
back in case of suspected heavy metal (arsenic)
poisoning is taken.
• In firearm injury cases, a skin portion of suitable size
around the entrance and exit wounds should be excised

21. P R E S E R VAT I O N O F
V I S C E R A
• Ideally there should be no delay between the
collection of specimens and their analysis in the
laboratory.
• If the delay is short, refrigerated storage may be
sufficient to preserve the samples.
• But the transportation of the viscera to the forensic
science laboratory and their examination at the
end would naturally take some time. To protect
from putrefaction to set in and render chemical
analysis difficult, certain preservatives should be
used.

22. P R E S E R VAT I O N O F
B L O O D
• The best preservative for blood samples is sodium
(or potassium) fluoride at a concentration of
10mg/ml which preserves blood for more than 3
months at room temperature.
• 0.5mg sodium citrate plus 0.1 mg mercuric
chloride is another suitable preservative.
• For suspected poisoning case excluding oxalic
acid, 10ml of blood is mixed with 30mg potassium
oxalate (anticoagulant) and 10mg Na fluoride
(enzyme inhibitor).
• For oxalic acid and ethylene glycol, 30mg sodium
citrate should be used instead.

23. P R E S E R VAT I O N O F
B L O O D
• Heparin and EDTA should not be used as an
anticoagulants since they interfere with the
detection of certain poisons (methanol).
• In case of Carbon monoxide poisoning, a layer to
1-2cm of liquid paraffin should be added
immediately over the collected blood sample to
avoid exposure to atmospheric oxygen

24. P R E S E R VAT I O N O F
O T H E R V I S C E R A
• In all cases of poisoning, inclusive of carbolic acid
but exclusive of other acids, rectified spirit is used
to preserve viscera as well as urine.
• Alternatively, saturated solution of common salts
should be used to preserve viscera other then
blood, In all cases of poisoning, inclusive of
carbolic acid but exclusive of other acids.
• 10% formalin is used as a preservative for tissues
meant for histo-pathological examination.

25. M E T H O D O F
O T H E R P R E S E R VA
T I O N
• The stomach, small intestine and their contents
should be preserved in one wide mouthed glass
bottle.
• Pieces of liver, spleen and kidney should be
placed in another bottle and urine in the third
bottle.
• When additional material is required to be sent, it
should be dispatched in separate bottles.
• Blood should be sent in vials.

26. M E T H O D
O F O T H E R P R E S E R V A T I
O N
• The solid organs are cut into small pieces to
ensure penetration of the preservative.
• The bottle should not be completely filled with
preservative however it is necessary that complete
immersion of the viscera is done.
• If the material is not completely submerged in the
solution, decomposition will take place with the
result that gases may form and either undo the lip
spilling the contents or even break the bottle.

27. M E T H O D
O F O T H E R P R E S E R V A T I
O N
• The stoppers of the bottle should be well fitted,
covered with a piece of cloth and tied or string at
the ends sealed using a departmental seal.
• Each bottle should be labelled properly, containing
autopsy number, name of deceased, name of the
organ, date, time and place of autopsy followed by
signature of doctor.
• The sealed bottles are then put in a viscera box
which is locked and the lock is sealed.
• The key of the box and a specimen of the seal is
put in separate envelope and it is also sealed.

28. D I S PAT C H
O F V I S C E R A
• The sealed box and the envelope containing the
key is then handed over to the police constable in
return of a receipt.
• He delivers is personally to the office of
Provisional Chemical Examiner after obtaining a
receipt for the same

29. O T H E R D O C U M E N T S
• Along with viscera box, some other documents are
also sent:
• A copy of Panchnama; brief facts of the case, and
the case sheet.
• A copy of autopsy report.
• A letter requesting him to examine the viscera and
inform the medical officer of his finding.
• Unless the viscera are sent to chemical examiner,
they are to be preserved for 6 months and then
destroyed after obtaining the magistrate assent, or
when the investigating officer informs the
laboratory that the case is closed.

30. T H A N K S