Pre Analytical Artifacts

Question 1

Drug concentration may be artificially changed due to

Answer 1

Collection process
Storage conditions
Container
Targeted analytes may be added to the specimen from the container

Question 2

Blind stick

Answer 2

Heart blood samples obtained by “blind stick” through the chest routinely collected in some jurisdictions
Some “collections” are obtained by medically trained individuals
Instances collections are performed by funeral homes,law enforcement or other untrained individuals

Question 3

Dead Drunk or Dead Sober

Answer 3

Blood Alcohol analysis is one of the most commonly requested toxicological examination performed in death investigation
Appx. ⅓ of cases are positive

Question 4

Blind sticks always begs the question

Answer 4

Trauma cases
Missing and hitting esophagus
Gastric contamination due to ruptured stomach

Question 5

Blind Stick Sample Collection Case Study

Answer 5

Logan and Lindholm (1996) report a case of gastric contamination of postmortem blood samples during blind stick
45 yr old female found dead at home
Hx of ASCVD and non-insulin dependent diabetes
Drawn by the funeral home director
Sample was a brown-discolored, largely immobile specimen
Submitted for tox. Analysis
Test results
ETOH .22g%
Amitriptyline 6.16mg/L and
Nortriptyline .35mg/L
Results c/w combined drug and alcohol overdose
Autopsy was preformed
COD determined to be acute pancreatitis
puncture marks from blind stick

Question 6

Validity of Chest Cavity blood

Answer 6

Case w. Massive trauma
Blood unavailable form heart, femoral or carotid vasculature
Blood may be scooped from chest cavity and submitted for analysis
High potential for contamination from stomach content

Question 7

Chest Cavity Blood Case Study

Answer 7

Budd
8 yr period,25 cases
Paired heart blood and chest cavity fluid collected
15 cases had postive alcohol findings
Divived into 2 groups
uncomprimised : no evidence of stomach/diaphrgam
Compromised: perforation,decomp. Or questions

Question 8

Diffusion of stomach alcohol

Answer 8

Issue of alcohol diffusion from stomach artifically raising blood alcohol concetration
Dates back to the late 40s and 50s

Question 9

Plueckhahn and Ballard study

Answer 9

Evaluated 230 consecutive cases
Heart blood and femoral blood collected
Distillation/colorimetric method
86 positive samples
Less than .05% probability of a statistical difference between the two measured []
Studied pericardial fluid as well
Pericardial fluid alcohol [] up to 20% greater than whole blood
Noted in study that this fluid may be susceptible to diffusion of alcohol from the stomach to investigate
Instilled alcohol into stomach of 20 cadavers
Significant increase of alcohol concentration in pericardial fluid
Insignificant increase in heart blood concentration

Question 10

is there a debate on acceptability of heart blood specimens for alcohol determination

Answer 10

Yes
Data from Sunshine and data from Freireich, as referenced by Harger and Forney (1963)
Exhaustive study by Plueckhahn (1967)

Question 11

Prouty and Rohrig

Answer 11

evaluated a series of over 500 paired heart blood and femoral blood specimens
GC
No significant difference between values in normal cases
Medical intervention, specimen volume to container size and trauma did impact the value
Trauma cases without medical intervention vast ,majority of heart BAC were lower than the paired femoral bloods

Question 12

Aspirated Vomitus

Answer 12

Agonal vomiting not uncommon
307 autopsies
Positive ETOH .05
Rt atrium,ascending aorta & IVC, Vit, Gastric
Suggested that agonal aspiration of
Vomitus w/ at least .80% ethanol
Associated with elevation of aortic blood alcohol
Compared to RT atrial and IVC blood alcohol concentration

Question 13

Pounder and Yonemitsu designed study

Answer 13

5 human cadavers-drug and alcohol free
Stimulated agonal aspiration of drug and alcohol laden vomitus
48hrs undisturbed at room temp
Blood samples were collected from 10 sites
Ethanol and drug concentration highest in pulmonary vessels
All should have been negative
ETOH and drug [] in aortic blood were higher than in the left heart
Suggesting direct diffusion into these vessels rather than diffusion via the pulmonary and cardiac blood

Question 14

Carbon Monoxide

Answer 14

CarboxyHB saturation determination by spectrophotometric methods
CO-Oximetry
UV/VIS
Falsely high COHb via Spectrophotometric methods
Putrefied samples
Heat denatures
Discolored reddish cavity fluid
Fat and lipids from leg
Fixed wavelength v Full Scan