Anne ImObersteg and Associates provides services for determining whether the integrity of a biological specimen has been compromised. Testing is performed through a contract with Baughman Labs. Baughman Labs utilizes standard microbiological techniques to determine the absence or growth of microorganisms in the specimen.

The methods of blood collection, the amount of preservative in the sample, storage conditions, and evidence of contaminants or alcohol-producing organisms are issues that scientists should consider when evaluating a blood alcohol case. One of the greatest risks to the integrity of a forensic sample is the growth of microorganisms in a sample which has not been properly collected or preserved.

Proper blood draw techniques are crucial to the integrity of the sample. The human body naturally contains a variety of microbes on the skin and in the body. The amount and variety of microbes on the skin varies from individual to individual. For example, an average person per square centimeter has anywhere between 100 to 100,000 microbes depending on the time of day, personal hygiene, and whether he/she has been exercising. Thus, the prospective puncture site must be properly cleaned with a non-alcoholic swab and with proper mechanical movement, to minimize the drawing of microbes into the syringe.

The presence of microbes in the blood indicates that the blood draw procedure was not performed in a sterile manner. Contaminated specimens are inherently unreliable, and can not be used forensically.

The presence of a preservative, such as sodium fluoride, does not guarantee that contaminants in the blood specimen will be killed or inactivated. By culturing a sample of the blood in a growth medium, living contaminants can be identified by Anne ImObersteg and Associates/Baughman Labs.

Some micro-organisms such as Candida albicans, can utilize glucose in the specimen and produce ethanol. (Blume P., Laktua D.J., Bacterial Contamination on BAC Stability, Am. J. Clin. Path. 60:700-702, 1973.) Alcohol production in the blood collection tube will occur fairly rapidly. Within 12 hours, yeasts such as Candida albicans will produce significant alcohol in the presence of glucose. (Saady et. al., Production of Urinary Ethanol after Sample Collection, Journal of Forensic Sciences, Vol. 38, No. 6, November 1993, pp. 1467-1471).

Not just Candida albicans potentially alters a blood alcohol result. The following is a partial list:

Candida albicans and other yeasts
Streptococcus fecalis
Klebsiella oxytoca
Pseudomonas maltophilia
Klebsiella pneumoniae
Enterobacter agglomerans
Enterobacter cloacae
Enterobacter aerogenes
Serratia liquifaciens
Serratia vulgaris
Proteus vulgaris
Morganella morganii
Morganella mirabilis
Citrobactobacter fruendii
E. coli

When the subject's drinking pattern would not elicit the level found in his/her blood, sample integrity testing should be considered. This is especially true when the sample may have inadequate preservative, or was not refrigerated immediately after collection.

Contact Anne ImObersteg via the above link to arrange integrity testing.