Evaluation of Add-on Testing in the Clinical Chemistry Laboratory of a Large Academic Medical Center/In Reply

Archives of Pathology & Laboratory Medicine, Apr 2005 by Frikke, Maureen J, Melanson, Stacy Foran, Lewandrowski, Kent B

To the Editor.-Melanson et al1 examined the rate of "add-on testing" in the clinical chemistry laboratory of Massachusetts General Hospital for a period of 1 week. They concluded that retention of laboratory specimens for 7 days places an unnecessary burden on the laboratory relative to patient care and laboratory operations. They advocated that specimens be discarded after 2 days.

Their analysis failed to identify use of laboratory specimens for the purpose of medicolegal death investigation. All states in the United States have laws that require investigation of deaths that occur under a variety of circumstances. Many of the persons whose deaths are investigated by the medical examiner or coroner are hospitalized, and the duration of hospitalization frequently exceeds 2 days. I would request that laboratory administrators who are considering implementing the authors' recommendations examine the role of their institution in the local system of medicolegal death investigation.

Most hospitalized patients of medical examiners die as the result of prehospitalization events. Only the admitting specimens (blood, urine, gastric contents) accurately record the effects of those events on the patient. In many cases, the events involve intoxications, poisonings, and metabolic abnormalities, which are rarely evaluated ante mortem to the extent that is required for proper certification of cause of death. The medical examiner or coroner uses the retained admission specimens for definitive testing. Death is frequently declared more than 2 days after admission. If all samples are discarded after 2 days, then critical forensic evidence will be destroyed, resulting in obstruction of the death investigation.

MAUREEN J. FRIKKE, PhD, MD

Office of the Medical Examiner, State of Utah

Salt Lake City, UT 84103

1. Foran Metanson S, Hsieh B, Flood JC, Lewandrowski KB. Evaluation ot add-on testing in the clinical chemistry laboratory of a large academic medical center: operational considerations. Arch Pathol Lab Med. 2004:128:885-889.

In Reply.-This letter to the editor raises an important issue regarding the retention of laboratory specimens for medicolegal investigation. The author points out the value of admission specimens for certification and investigation of cause of death. If laboratory specimens are retained for only 2 days, admission specimens may not be available as forensic evidence.

One aspect of our article addressed retention of routine laboratory specimens to accommodate add-on testing. Our data suggested that specimens could be retained for 2 to 3 days and still accommodate add-on testing, as well as maintain regulatory compliance. Although we did not directly address the retention of specimens for medicolegal purposes, we acknowledged that specimens are retained for reasons other than addon testing. We also suggest that each laboratory "define the storage time that is most appropriate for their institution."1

At our institution, patients under the jurisdiction of the medical examiner are often under the care of physicians in the emergency or surgical departments. Admission specimens are usually fewer than 2 days old, or prior knowledge of the medicolegal issues is apparent. In these cases, admission specimens are readily available. The state of Massachusetts and/or the medical examiner's office does not require that hospital laboratories retain specimens for a specified period (ie, more than 2 days) for medicolegal death investigation. However, other states or institutions may have different requirements, as the author suggests. Certain hospitals may also have more medicolegal cases. The requirements and demographics of these institutions will certainly affect the decisions made regarding the length of routine specimen retention.

A final point concerns the lack of an appropriate chain of custody for clinical specimens. Use of clinical specimens for medicolegal applications is widespread, albeit this application is potentially risky given the relatively high rate of mislabeled specimens especially from emergency departments. We have personally observed cases where specimen mismatches produced near-miss catastrophes when applied to the medicolegal prosecution of patients.

STACY FORAN MELANSON, MD, PhD

Clinical Laboratories Division

Brigham and Womens Hospital

Boston, MA 02115

KENT B. LEWANDROWSKI, MD

Division of Laboratory Medicine

Massachusetts General Hospital

Boston, MA 02114

1. Foran Melanson S, Hsieh B, Flood JG, Lewandrowski KB. Evaluation of add-on testing in the clinical chemistry laboratory of a large academic medical center: operational considerations. Arch Pathol Lab Med 2004:128:885-889.