In coag collections, every detail counts

Ideally, all these components are from one manufacturer. This, in Dr. Adcock’s view, is an important element of coagulation sample collection. “They’re actually a pretty complex system. If you change a component of that system, you should test and validate it,” which is addressed in recommendation No. 3.5. In that regard, a collection tube is no different from a reagent; just as tests have to be validated with a new reagent, the test also needs to be validated when the collection tube manufacturer changes. “I think that might surprise some people,” she says.

“We’ve found that there are differences between FDA-approved tubes,” Dr. Marlar reports. Nevertheless, laboratories may not appreciate those differences if they switch from one manufacturer to another, whether for reasons of scarcity, price, or some other motivation. “We’ve heard a lot of discussion about, I can just use any tube out there, and that will be OK.

“That’s not correct,” he says.

Dr. Adcock’s encompassing perspective looks ahead as well as back. She predicts coagulation collection issues will become more weight-bearing as new drugs, especially anticoagulant and factor replacement drugs, become available, just as the field needed to adapt its collection practices when direct oral anticoagulants came on the scene. “That impacted many of our assays,” she says.

The pandemic’s tentacles have latched onto coagulation testing, most obviously with the shortage of blue-top tubes. As labs struggle to acquire citrate tubes, they may also acquire some unintended consequences along with their supplies.

Which brings us back to those aforementioned mystery tubes.

They can be purchased from common online sellers, Dr. Marlar notes, but he and his colleagues haven’t been able to identify the manufacturer.

“Fortunately, we recognized it before we tested it,” he says. The tube made its way into circulation via an outside clinic, which said it purchased the tubes in response to the shortage. Dr. Marlar’s lab was firm in its response: “We told them not to use them anymore.”

In the meantime, his lab made its own purchase to do a comparative study. ”We know nothing about them,” Dr. Marlar says. “We’re not even sure where they’re made.”

If a lab did decide to use these tubes, it would need to be aware the tubes lack FDA approval; any LDT use will require validation. “And they’d have to validate every lot,” Dr. Marlar adds, “because we don’t know that any quality control has been done on these tubes,” or if it has, how.

The easy availability of such tubes “has, I think, been a surprise for many in the lab community,” Dr. Marlar says. “We’re just hoping that we were the unique case, and that it’s not prevalent in the U.S.”

Laboratories aren’t to be faulted for looking for less-expensive tubes—it’s a common enough endeavor. And the pandemic has pushed the search for supplies into the farther latitudes. Given the pressures of the pandemic on supply chain, the FDA has given emergency use authorization for one manufacturer’s citrate tubes, “because we have a massive shortage here,” Dr. Marlar says. “We may be seeing those rogue tubes in the United States now.”

Lab staff shortages, hardly a new problem, have also worsened during the pandemic. The nuances of collection can also get lost in the personnel shuffle. Sometimes technologists will be sent to do blood draws. Or, says Dr. Marlar, “It may get turfed over to the nursing staff,” who oftentimes lack recent experience in the task, or who may take the sample from an IV line or a port, which can lead to errors in sample processing.

When individuals other than trained phlebotomists draw blood, adds Dr. Adcock, hemolyzed samples are more common—they’re more likely to come from emergency departments, for example.

Another surprise could await some labs, although this one will be more welcome: Fixing coagulation collection errors might be easier than finding them.

The recommendations are not high hurdles in need of equally altitudinous leaps. Dr. Marlar advises labs to simply walk through the document and ask themselves if they’re following each recommendation. If not, they need to ask, Why not? And then delve into the literature, which, as he reiterates, is sound.

If, for example, it turned out his own lab didn’t follow the recommendation to use 3.2 percent instead of 3.8 percent citrate, “we would look at the literature and the evidence and then make the switch.” It’s not a big ask, he says. “At every lab I’ve worked we’ve made that switch.” Obviously the change requires validation. But, says Dr. Marlar, “It can be a small study. It does not need to be hundreds of patients.” Ten to 20 patients should be sufficient to ensure that replacing 3.8 with 3.2 works and can be incorporated in the lab’s standard operating procedures.

Like restaurant inspections, following the recommendations shouldn’t be a one-and-done, bounce-out-the-door endeavor. “These things change,” Dr. Marlar says. “When these documents come out, every laboratory needs to look at them and say, We’re doing all of them, or we’re not.” As added incentive, he says, laboratory inspectors may ask questions of their own. Though these are not checklist-centric, it’s reasonable for labs to ask themselves why they’re doing something or not doing something that’s supported in the evidence. “As a laboratory director, you have to justify why you’re using 3.8 and not 3.2.”

Walking through the recommendations might also be a more direct path to discovering problems, rather than waiting for errant results to emerge and (it’s hoped) be caught.

Over the course of his career, Dr. Marlar estimates he’s seen samples that have violated each one of the recommendations. “But we may not know about it. If we do, we won’t send it.”

“I’ve seen things handwritten on tests, or lab labels that have been put on the wrong tube,” he says. Nor is his experience unique. “Every laboratorian, supervisor, director has always had these problems,” he says. “I think every laboratory needs to be vigilant.”

Though there are multiple checks along the way as samples are drawn and sent to the lab, sometimes errors are caught more casually. A technologist may see that a tube is underfilled and reject it, for example. Or a clinician will eye a reported value and realize it’s nonsensical. “Sometimes it happens—hopefully, the clinician will notify us that it doesn’t look right,” Dr. Marlar says, such as a patient receiving heparin whose results have consistently been within the therapeutic range several days and then suddenly are reported as normal.

In Dr. Adcock’s experience, it’s usually the medical technologist who catches the problem. Or, she might catch a pattern of results that look questionable when reviewing results.

She recalls one case involving a patient who was 24 hours post-surgery. “His PTT was shorter than is probably physiologically possible. So we knew, by looking at the result, that the whole sample was probably suspect,” Dr. Adcock says.

In other cases, fills are problematic. She recalls another case, this one involving a phlebotomist who was having trouble filling the blue-top tube completely. Knowing that an underfilled tube would be rejected, he uncapped the tube and added contents from a serum tube. Doing so can shorten the APTT because of the addition of activated coagulation factors.

It can be harrowing to navigate the line between sample quality and need for results, as the authors note.

“From my perspective as a laboratorian, I only want to put out correct results,” Dr. Marlar says. At times he’ll receive samples in the lab that are not valid; when he speaks with the clinician, they might tell him to run the sample anyway.

As the recommendations point out, rejecting a sample has consequences. “You may not get another one,” Dr. Adcock says. It may also delay urgently needed results.

It’s an onerous situation. Says Dr. Marlar: “I’d rather take flak from the clinician by asking for another sample. Because when somebody acts on a wrong answer, bad things happen to patients.”

Ideally, the recommendations will put an end to these dilemmas. Simply put, says Dr. Marlar, if labs follow the recommendations, those hard conversations are less likely to occur. Inappropriate samples won’t land in the lab for testing, and erroneous results won’t be sent back. And in another Royal Family tradition, perhaps no one will need to talk about it.

Karen Titus is CAP TODAY contributing editor and co-managing editor.