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CAP Home > CAP Reference Resources and Publications > CAP TODAY > CAP Today Archive 2001 > Sidestepping common deficiencies
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cap today

Sidestepping common deficiencies

May 2001
Vida Foubister

Checking for silicates
Where inspectors err

Whatever a laboratory’s complexity, there’s "something for everybody" to learn from a rundown of the most common discipline-specific deficiencies found during CAP inspections, says Thomas F. Ruhlen, MD, West Central regional commissioner for the Laboratory Accreditation Program.

Dr. Ruhlen highlighted these discipline-specific deficiencies in an educational audioconference last year. "It was a way to bring them to people’s attention," he says.

Not surprisingly, the checklist items cited most frequently are those that are new and those that were changed recently, says Dr. Ruhlen, medical director of laboratory services at Olathe (Kan.) Medical Center. So, from hematology to blood gas and everything in between, here are the LAP checklist questions most likely to catch your laboratory off guard.

Hematology

Question 02:3712 asks, "Are recommendations provided to clinicians concerning which laboratory tests to use for monitoring heparin and/or oral anticoagulant therapy and the therapeutic range for the tests?"

In the past, laboratories simply reported either normal or abnormal results for coagulation tests. Now that anticoagulants are commonly used to treat patients for long periods, clinicians need more information to monitor the therapy adequately.

"When you put a person on a blood thinner, their coagulation values are going to go out of normal range," Dr. Ruhlen says. "We’re trying to encourage laboratories to provide clinicians some guidance as to what they should expect."

The solution is to tell clinicians which tests are recommended for monitoring heparin and oral anticoagulants and then to report the results of those tests with the reference ranges that are applicable for anticoagulation therapy. Laboratories that are already fulfilling this requirement should ensure they have a documented method for doing so.

This checklist question also recommends reporting prothrombin times using the International Normalized Ratio. That’s because the reagent used in this test varies in sensitivity across manufacturers and product lots.

"A lot of times patients on anticoagulants are outpatients. Their doctor may be in another city or state, or they may go on vacation and have to get their blood checked," Dr. Ruhlen says. "They can’t always go to the same lab and have the test done, so this helps them get more uniform test results."

Chemistry

Question 03:2500 asks, "Are calibration procedures for each method adequate, and are the calibration results documented?"

The tricky part is understanding the difference between recalibration and calibration verification and performing these checks at appropriate intervals. Then it’s simply a matter of documenting the criteria used to define these intervals.

Adequate recalibration intervals are determined by an instrument’s need for calibration—which the manufacturers usually help define. Some instruments need to be calibrated daily or even more frequently, while others don’t have to be checked for months.

It’s up to each laboratory to establish its own recalibration criteria. In addition to the system’s stability, consider a change of reagents, quality control values outside an acceptable range, major machine maintenance or service, and data that fail laboratory acceptance criteria.

The second interval, calibration verification, is defined partly by regulation. The Clinical Laboratory Improvement Amendments of 1988 require calibration verification to be performed at least every six months. "The only event that resets the calibration verification clock is the performance of another calibration verification," Dr. Ruhlen explains. "A successful recalibration does not reset the calibration verification clock."

Another difference between these two intervals is that the material that’s used for the recalibrations and calibration verification should be different. "You’re going to use some kind of high-quality material to recalibrate, and you would not want to turn around and use those same calibrators for your calibration verification," Dr. Ruhlen says.

Urinalysis

Question 03A:3085 asks, "Is there a documented procedure for correlation of microscopic sediment findings (such as casts, red blood cells, or white blood cells) with macroscopic results (presence of protein, positive occult blood, positive leukocyte esterase, etc.)?

This question doesn’t require microscopic confirmation of all positive macroscopic findings. "Years ago we used to always dipstick the urine and then look at it in a microscope," Dr. Ruhlen says. "People started to realize these dipsticks are getting pretty good and if [the result is] negative, chances are when you look under the microscope you’re not going to see anything significant. And so a lot of labs usually test urine just using a dipstick."

Instead, the question simply requires laboratories to correlate the results of microscopic and macroscopic findings when both means of testing are performed. "If you see under the microscope that there are a lot of red blood cells, then your test strip for hemoglobin ought to have some degree of positivity," Dr. Ruhlen says.

Laboratories need to document that they have a method to help ensure that both means of testing correlate with one another.

Toxicology and special chemistry

Question 03C:3040 asks, "If automatic pipetting is used, has the laboratory evaluated the testing system for carryover effects?"

Some laboratory instruments with automatic pipettors might not always completely clear or clean the pipette between patient samples. Thus, a sample with a high concentration of the analyte in question might contaminate the next specimen, giving it a falsely elevated result. Laboratories need to test their machines for carryover effect and, if it is found, take appropriate precautions.

"It might mean you have to go back and repeat testing of a low sample that comes after a high sample," Dr. Ruhlen says.

A laboratory’s automatic pipettors, however, need to be tested only once. This can be achieved by running known high samples of common hormones, such as thyroid stimulating hormone or human chorionic gonadotropin, followed by low samples. Once this test is completed, an appropriate course of action must be outlined to counteract any identified carryover effect. Laboratories must ensure that they document the process and retain this for their records.

Microbiology

Microbiology checklist question 04:2244 on the collection of stool samples aims, in part, to help laboratories control costs. It’s not uncommon for laboratories to get multiple, repeat stool culture requests for one patient within the same day or over a short hospital stay.

"The thinking is that the more times you try, the more likely you are to get a pathogen," Dr. Ruhlen says.

The thinking is not only wrong but also wasteful of laboratory resources. "When you culture stool, you get all kinds of organisms growing out, and to pick out pathogens consumes a lot of resources," he notes. "There’s a lot of effort to do a stool culture."

Further, there may be a simple test that gives a more direct answer. Antibiotic-associated colitis can be detected, for example, by testing for the presence of Clostridium difficile toxin.

The checklist question asks, "Does the laboratory have guidelines (developed with clinicians) for the number and/or timing of collection of stool specimens submitted for routine bacterial testing?" It’s basically a reminder that laboratories need to communicate with clinicians about when repeat testing is appropriate.

Two rules of thumb suggested for clinicians in the microbiology checklist are that they not submit more than two specimens per patient and that they seek prior consultation before submitting specimens from inpatients after the third hospital day. The latter guideline is based on the knowledge that patients’ gastrointestinal tracts tend to be colonized by hospital flora, which masks the patient’s flora present at admission.

"These aren’t absolute guidelines that everyone has to follow strictly," Dr. Ruhlen says. "There may be clinical situations where [additional testing] is perfectly appropriate. The intent is to avoid cultures where the results are likely to be useless or even misleading."

Anatomic pathology

A top deficiency from the anatomic pathology checklist comes from this recently revised question, 08:1182, on frozen section turnaround time: "Are at least 90 percent of frozen section interpretations rendered within 20 minutes of specimen arrival in the frozen section area?"

The new guideline is based on a Q-Probe study of frozen section turnaround time published in the Archives of Pathology & Laboratory Medicine (Novis DA, et al. 1997;121: 559-567). It requires specimens to be prepared, analyzed, interpreted, and reported within 20 minutes. Previously, frozen section slides had to be ready for a pathologist to analyze within 15 minutes.

"A lot of labs just didn’t realize that it changed or they’re not tracking their turnaround time, so they can’t say whether they’re hitting that [target] or not," Dr. Ruhlen says.

Complicated cases that require multiple frozen sections, however, aren’t expected to meet this new standard. One example is a skin lesion with multiple margins that requires several frozen specimens for a complete interpretation. "Clearly it would be ridiculous to say you have to do them all in 20 minutes when that’s often just impossible," Dr. Ruhlen says.

Cytopathology

One of the cytopathology laboratory’s common deficiencies is a failure to develop procedures to avoid cross-contamination of specimens. Checklist question 08A:0440 asks, "Is there a documented policy for ensuring that nongynecologic specimens with a high potential for cross-contamination are processed and stained separately from other specimens?"

"The principle behind this is that, when you have a highly cellular specimen, some of the cells may dislodge and stick on a slide from another case and contaminate it," Dr. Ruhlen explains.

Because it might not be obvious that a specimen is highly cellular, a toluidine blue or other rapid stain can be performed on a suspect wet preparation. Then, if it is found to be highly cellular, several precautions can be taken. They include minimizing cross-contamination by using cytocentrifuge, filter, and monolayer prep methods, staining direct smears made from the sediment of highly cellular cases after the other cases, changing or filtering staining fluids between each of the highly cellular cases, and detecting contamination by inserting a clean, blank slide in each staining run and examining it for cells.

A laboratory need not take each of these precautions. Says Dr. Ruhlen: "CAP is not saying you have to do any particular one of those precautions, but you do have to come up with some kind of solution."

Cytogenetics

A top cytogenetics deficiency is a problem that’s not unique to this discipline. However, the problem is compounded by the fact that some cytogenetics laboratories are using computer systems that have trouble accommodating the required data.

Question 09:3200 asks, "Are preliminary reports (especially verbal, telephone reports) documented on the final report?"

"Some of the cytogenetics testing procedures take several days or even weeks to complete and they may issue an interim report," Dr. Ruhlen says. "When you turn out the final report, you need to include something about what was reported in the preliminary report," because it might have affected the patient’s care.

Even if the cytogenetics laboratory information systems can’t handle preliminary reports, the final report must include a reference to the preliminary report’s conclusions. However, it’s unnecessary to duplicate all the facts and figures, such as photographs of chromosome sets, that were part of the initial report.

Blood gas

Question 26:0015 is about unacceptable proficiency test results. It asks, "Is there evidence of evaluation and, if indicated, prompt corrective action in response to ’unacceptable’ results on the Surveys report?"

Blood gas laboratories often have their own CLIA number and their operations are often separate from the main laboratory. Problems with this question arise when respiratory therapists or others operating this type of satellite laboratory aren’t familiar with the accepted procedures for investigating unacceptable proficiency test results.

"So they may do the proficiency test, the results come back, they say, ’Hmm, that’s nice,’ and they put it in a drawer and forget about it," Dr. Ruhlen says.

One option is for the main laboratory to assist the blood gas laboratory with this process, which should include investigating the failure, applying corrective action, and seeking evidence that the problems have been resolved. This process should be documented.

Blood gas laboratories can also look to a 1987 article in the Archives of Pathology & Laboratory Medicine (Hoeltge GA, et al. 1987;111:1011- 1014) for categories of the most likely problems. These include methodologic problems, technical problems, clerical errors, Surveys material problems, and problems with no satisfactory explanation.

"We’ve been using this in my laboratory for several years and it helps people to narrow down the problem," Dr. Ruhlen says.

Vida Foubister is a freelance writer in Chicago.

   
 

 

 

   
 
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