4.24: Chain Of Custody

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A patient is taken from the scene of an accident directly to the emergency room of a hospital. The physician notes that the patient is not responding well to stimuli. In order to differentiate between a possible neurologic trauma and alcohol-induced CNS depression, a blood alcohol measurement is ordered. A phletobomist draws the blood, initials the slip, and brings It to the laboratory where the specimen is logged in by a technologist. The alcohol level is recorded as 1500 mg/mL. Levels above 800-1000 mg/mL (0.1%) are defined as intoxicated by most state laws (see p 641, Chapter 34). A policeman comes into the laboratory with a subpoena for the laboratory’s results. The patient is accused of driving while intoxicated, causing a fatal accident. A week later, a defense attorney calls and requests information about the specimen results.

After giving both the policeman and the defense attorney appropriate information, as cleared by the hospital’s risk management team, the technologist is notified that she will be placed on the witness stand in the upcoming trial for this case. The phlebotomist is also notified of a subpoena to appear in court.

QUESTION

What information did the policeman and defense attorney request?

Questions to Consider

What is the difference between the specimen labeling and handling procedures for forensic/legal cases and those used in routine patient cases?
What is a chain of custody?
What legal question will be debated in the court which involves both the phlebotomist and the technologist?

Answer

The policeman asked for the laboratory result on the patient’s alcohol level in order to establish that the patient was intoxicated. He will try to prove beyond a reasonable doubt that indeed the facts are correct.

The defense attorney wanted information regarding the alcohol analysis, including any QC performed at the time, etc. In addition, the attorney wanted to know who logged in the specimen, who did the actual analysis, and how the sample was stored, before and after analysis. In addition, the attorney wanted documentation on all these points. The defense attorney will try to establish that the data could be invalid or that it was possible that the sample could have been switched, tampered with, or altered.

Answers to Questions to Consider

The difference between specimen labeling and handling for legal cases and those used for routine patient care is that the physical condition, knowledge of each person who was in possession of the specimen, and limited access to the specimen must be documented in forensic cases (p. 73-74).
Chain of custody is a legal document, usually in written form, which describes everything which occurred during the transportation, analyses and storage of the specimen (p. 73-74). This includes the name of the person drawing the specimen and the names of each person who received the specimen, the condition of the specimen at time of transfer from one individual to another, and the condition of the specimen at the time of analysis. Also, if the sample is stored, the storage area must be secure, that is, locked with access available only to a limited number of authorized personnel. The special form used in these cases is called a Chain of Custody form. The special form used in these cases is called a Chain of Custody form.
The legal question which will be debated is whether or not the specimen was a legally valid one, even though a chain of custody form was not filled out. If the specimen was drawn by the phlebotomist and given directly to the technologist who performed the analysis, this may well be accepted as a proper chain of custody. If, however, other individuals were involved with the specimen who could not document their custody, then most often the laboratory data is not acceptable to the court.