February 2008
Feature Story

Anne Paxton

Without delay or hesitation; with no time intervening. That’s the formal definition of “immediately,” but as a practical matter, the length of time it takes clinical laboratories to call and relay critical values to a caregiver is always greater than zero.

How much greater, on average? Until now, those numbers haven’t been nailed down.

A new CAP Q-Probes study, “Critical Values: Physician Notification Processes,” released in December 2007, is the first to collect the data and parse those numbers—and the results are heartening, say CAP experts in laboratory quality practices.

“When CLIA regulations say we have to immediately call critical values, what does that mean? This study was designed to answer that question,” says study coauthor, Elizabeth A. Wagar, MD, laboratory medical director for UCLA Clinical Laboratories, Los Angeles.

The key finding of the Q-Probes study is that critical test results were called a median of four minutes after the result was known in the laboratory, and 56 minutes from the time the specimen was collected.

“That actually seems fairly reasonable, given that these could be life-threatening values,” says Dr. Wagar, who adds that she is encouraged by the results. “Laboratories are doing a pretty good job of getting these results out in a timely way.”

What prompted the study was concern at the College that the requirement to immediately call critical values was created “in a bit of a vacuum,” says study coauthor Paul N. Valenstein, MD, president of Pathology and Laboratory Management Associates, which serves four hospitals and a reference laboratory in Ann Arbor, Mich. “To my knowledge, this Q-Probes audit is the first multi-institutional study that has looked at how long it takes to actually notify a licensed caregiver of a critical laboratory value in a ‘real-world’ setting.”

In the health care world today there is a lot of emphasis on calling critical values, but very little is known about what is achievable in practice, Dr. Valenstein says. “Laboratories are required to monitor how quickly critical results are called, but up until now there’s been no context in which to place the results of monitoring. For a laboratory director or the medical staff, there’s no sense of what’s possible or reasonable.”

Hospital accreditors, including the Joint Commission on Accreditation of Healthcare Organizations, will cite institutions for not monitoring how quickly caregivers are notified, “but the Joint Commission has very little to say about what results should be considered critical, what notification time frames are reasonable, or what methods of notification produce better outcomes for patients.”

Dr. Valenstein also faults some discussants for implying that seconds count when calling caregivers about critical values. “Certain individuals are rather shrill about the importance of immediate notification,” he says, “but we tend to forget that for the average specimen, more than 50 minutes has already elapsed from the time the specimen was collected and the time the test result is known in the laboratory. And many patients presumably had their abnormality for some time before the specimen was collected in the first place.”

Dr. Valenstein suggests that the minutes that elapse between obtaining a result and making the call are not as important as the time from collection to testing. “Calling takes place fairly rapidly after critical results are known, and the time from collection to testing is typically much longer. To me that suggests that vociferous arguing over minutes is ill-advised.” The study, in fact, recommends that a reasonable requirement would be to make the call within 15 minutes of the result having been reported.

Another area of uncertainty is whom to call with a critical result. The Joint Commission requires that calls go to a licensed caregiver. “Our study supports that requirement,” Dr. Valenstein says. “We found that calls placed to secretaries and ward clerks saved very little time, and we had evidence that this communication is less reliable because it’s less likely to involve read-backs. But there is still debate about whether to call doctors or nurses about the results,” he notes. “Our study shouldn’t point laboratories in either of these two directions.”

“For example, if one of my technologists calls a doctor directly about a positive blood culture, the doctor learns about the result a little sooner than if a nurse had been called. But before prescribing antibiotics the doctor often has to call a nurse and find out what drugs the patient is already receiving. If my technologist calls a nurse instead, the nurse can assemble this information before making the call to the physician.”

“Which is better? I don’t know, and I think it’s premature just to set a standard without evidence.”

In line with previous studies of turnaround time, smaller and more rural institutions tended to perform better in relaying critical value results. “While some people who work in large urban hospitals like to snicker at their rural counterparts, in many objective measures of laboratory quality small hospitals perform better. Critical result notification is one of these areas. Presumably there are fewer people to call in smaller hospitals, and laboratory staff know better how to get hold of caregivers,” Dr. Valenstein says.

The study found that a small percentage of critical value calls end up being abandoned. “It’s something that needs to be addressed in each laboratory procedure,” Dr. Wagar says. “It can be a difficult situation, but personally I don’t allow that calls be abandoned. I insist that somebody eventually be called who could be considered a licensed caregiver.”

Other variables can affect the speed of reporting critical values. About half of the participating facilities call critical values before they are released from the laboratory information system, and they notify caregivers a little faster than sites that release results from their computers before calling.

Opinions differ on the advisability of calling before verification. Frank Schneider, MD, also a study coauthor and a pathology resident at Duke University Medical Center, Durham, NC, says the advantage of issuing a critical result right away, especially in a hospital or health care setting that has electronic medical records, is that the result is available immediately. “So someone on the ward caring for that patient could already have seen the value even as you’re making the call,” he says.

In his view, if it takes 15 minutes to verify the result, it makes more sense to call right away. “No one has studied it, but there is a theoretical possibility the value could reach a care provider before you actually get hold of them, maybe because the paging system is down or the number is wrong.”

Once the call is made, the QProbes data indicate, the protocols that are followed vary. Most calls go to licensed caregivers—physicians, registered nurses, and mid-level providers—who routinely “read back” the critical value to confirm it.

“Read-back is a practice that was emphasized both by the Joint Commission and the College,” Dr. Wagar says. “As a consequence, over the past three years we have reached a much higher compliance with the requirement. We found really a very high percentage of read-back.”

Dr. Schneider points out that at teaching hospitals the people receiving critical values calls are often residents, who frequently switch duties. “Someone might order an overnight value while covering for someone else. The problem is that when the critical value is called to the ordering physician, that person might not be responsible for that patient anymore. That might necessitate a second call and cause a delay.” In his experience, the read-back policy is very closely followed, and leaving a result with a ward clerk or unit secretary would be unusual. “Laboratory technologists are very well aware that they play a very important role in communication between the laboratory and care providers. I don’t think any of them would just blow off the read-back and let it go.”

The Q-Probes study finding that read-backs are done slightly less often in institutions that did not use defined scripts is also interesting, Dr. Wagar says. “Scripts are perhaps something that might be important to laboratories, and we could implement them with some ease within laboratories to ensure we are getting the right words and right information out. It’s a way to standardize how we relay important information to caregivers.”

However, she expresses concern about the Q-Probes study finding that in many cases the medical staff did not approve the time frame for calling. “Ultimately it is the laboratory director’s decision,” she says. “But a wise laboratory director works with the medical staff organization to define it. There are a number of routines by which the time frame could be approved or reviewed.”

Perhaps the most important question left unanswered by this study is where critical result cutoffs should be set in the first place. “We expend a great deal of effort treating every critical result as if it were imminently life-threatening, but how do we know we are setting our cutoffs correctly?” Dr. Valenstein says. “It’s difficult to argue with the Joint Commission’s position that critical values should be set in conjunction with the medical staff, but how is the medical staff supposed to make those determinations?” When looking at a group of hospitals, he says, it’s typical to find that the medical staffs make very different decisions about where to set critical value cutoffs. “Maybe the differences reflect their patient mix, but I am doubtful,” he adds.

In Dr. Valenstein’s experience, the medical staff often sets critical value cutoffs on the basis of what other nearby hospitals use. “Nobody sits down and statistically determines the risk profile for a particular cutoff value. But maybe they should.” Dr. Valenstein gives an example: “The median facility considers potassium levels above 6.2 mL/L to be ‘critical.’ In the largest hospital our group serves, four percent of patients with a potassium of 6.2 will die in the next 24 hours, compared to one percent for patients with a potassium of 5. Does this make a potassium of 6.2 critical? If it does, what does this say about the 10 percent of laboratories that have set their threshold at 6 or lower, or the 10 percent that have set their threshold at 6.5 or higher?”

This Q-Probes study found that for 89 percent of hospital-based laboratories, the hospitals’ medical staffs approved the list of critical values. “What happens at the other 11 percent I have no idea— the cutoffs are in the lab computer, but how they got there and who authorized them was not known at the facilities that participated in our study,” Dr. Valenstein says.

Complaints about calling non-critical results are heard fairly frequently from clinicians, Dr. Wagar says, especially when patients have renal disease or other kinds of chronic conditions. “The classic example is diabetes. Many patients may need medication at values greater than 400, but the result may not be critical for a person who has run high glucose levels for some time.”

“Physicians sort of expect the laboratory to be able to read their minds on what is a critical value. We can’t, so we set them conservatively.”

“Ideally,” says Dr. Schneider, “the medical directorship of the hospital gets together with responsible people in the laboratory and comes up with policies of what they want reported. That becomes especially important in cases in which the patient has a critical value every time you draw blood.”

“Providers are well aware of it, and some critical values will not change how the patient is treated, even though they [providers] get called about it every four or eight hours. And if you shout for help 20 times, someone might not show up time 21.” Only communication between the laboratory and care providers can address this problem, he says.

Nevertheless, a separate Q-Probes study, “Physician Satisfaction with Clinical Laboratory Services,” released last June, found that 87 percent of physicians were satisfied with the clinical laboratory’s record of calling critical values, and Dr. Wagar says this is in line with her experience. “I would expect fairly positive reactions from clinicians. Most physicians, even though they don’t like to be called in the middle of the night, do appreciate getting a critical value of significance.” Dr. Schneider says data acquisition on how critical values are reported is only beginning and the time frames are important. “I think this information can be taken to medical staffs to say, ‘Hey, what do you think, how did we perform, and should we get together and actually agree on a time frame?’” he says.

The study confirms that laboratory directors should go back and review procedures and policies on critical values and discuss them regularly with their medical staffs, Dr. Wagar says. “That is a piece that we have to be conscientious about, and it’s a piece that I don’t think you can reiterate too often.”