Robin Cook, Marker

With his latest novel, Cook continues his string of stories about Jack Stapleton and Laurie Montgomery, medical examiners in New York City. In Marker, the mystery begins when Laurie posts two bodies on consecutive days that have no obvious pathology. Both were young and seemingly healthy, the only strange circumstance being they were recovering from routine surgeries at Manhattan General Hospital. Laurie puts these two cases together with a couple other cases that had come in the week before, and this gets here interest up. When two more cases come in, she is totally convinced that there is homicide at the root of these mysterious deaths.
Meanwhile, Laurie and Jack's personal relationship has come to a standstill. Jack is unable to commit, and Laurie breaks things off. Into the void left by Jack, she puts a relationship with Roger Rousseau, the chief of medicine at Manhattan General. They met while Laurie was filling him in on the series of suspicious deaths, in hopes that Manhattan General may be able to do something to identify the problem, or at least take some action to prevent future deaths. But things don't get too far before she discovers that she is pregnant with Jack's baby.
The case heats up when another group of suspicious cases comes in to the medical examiner's office. Laure has been able to connect the deaths to a group of six cases from the previous fall at another AmeriCare (managed care) hospital across town. None of the deaths had any obvious cause, and none had any sign of foul play on the toxicology screens. Laurie talks Roger into checking into personell reports from Manhattan General and the other AmeriCare hospital to see about personell that overlap with the two time frames, and who worked the night shift, when all of the deaths occurred. Roger is able to work up a list of possible suspects, but after leaving Laurie a message about some of his findings, he meets a sudden death at the hand of the killer.
Laurie is working hard to put all of the pieces together to come up with a cause of death and also a common thread that may establish motive. And though she continues to have no luck on cause, she notices that all of the patients had a genetics screening test along with their admit labs, and though the results had been removed from the paper records, all had some type of positive result in their electronic files. But just as she is putting some of the key ideas together, she begins suffering from serious obdominal pain, and a quick phone call to her doctor confirms that her pregnancy is in serious trouble, and suspecting a ruptured ectopic pregnancy, she is rushed to the emergency room at Manhattan General. But Laurie is now concerned that she may be the next victim in her own series, as she fits the profile: a young, healthy, post-operative patient, who is positive for a marker, a gene mutation that marks a predisposition to serious health issues (she has found out she has the BRCA1 marker, for the mutated gene that increases risk of breast cancer). Jack rushes over to be with her, and her surgery to repair the ruptured ectopic pregnancy goes routinely. And her recovery starts off routinely, but a rush of patients means she is moved from the recovery floor to a regular floor, where many of the deaths occur. Jack meanwhile has left to run down some leads, and figures out the mode behind the killings, the administration of a lethal does of potassium, a naturally occuring ion in the body. Potassium causes an imbalance of chemicals in the muscles and causes immediate cardiac arrest, but it is difficult to detect on autopsy because it naturally occurs in the body and is naturally released from the muscles upon death, meaning the level is usually elevated after death, therefore masking the lethal injection.
Jack returns to the hospital and rushes to Laurie's room, to discover a nurse (named Jazz) standing over her, and her vital signs rapidly declining. He calls a code, and informs the attending cardiologist that she has high potassium level, allowing them to administer a counteragent and bring her back from cardiac arrest. Jack follows Jazz out after her shift to confront her, since she is one of the suspects already and her presence in the room just confirms his suspicion. But when he gets to her car, she is shot by someone lurking in her back seat.
Detective Lou Soldano, a police detective and friend of Jack and Laurie, helps to piece the details together. Jazz was one of a number of operatives across the country for a group that was working in conjunction with AmeriCare (a managed care company) to eliminate patients who tested positive for gene mutations linked to expensive diseases, such as cancer. The company had realized that Jazz was in danger of being discovered, and wanted to tie up their loose ends, but Jack and Laurie got there first.
As he often does, Cook has woven a good story together with some thoughtful issues that deserve attention. What does the mapping of the human genome mean for the future of medical care. Obviously it holds great promise for identifying causes and possible solutions for many genetically influenced dieseases, but there is also great danger, reminiscent of the movie Gattica, in misusing this knowledge. These are issues we must face in the coming years as we come to terms with new technologies and their ethical implications.