A six year series of the same medical error

June 22, 2009

surgeryI was made aware of a series of medical errors in brachytherapy by the Health Care Renewal blog. The original article is here. Brachytherapy is a treatment for prostate cancer where small radioactive seeds are implanted in the prostate.

As a quick summary, at the VA hospital in Philadelphia, over a six year period, 92 out of 116 brachytherapy treatments were performed incorrectly, often leading to serious complications. The VA had contracted out the treatments with one of the contractors being from the University of Pennsylvania and board certified in radiation oncology.

In the article:

Two days later, the Joint Commission, which helps set standards in the hospital industry, surveyed the Philadelphia V.A. and on the next day accredited the hospital. “This organization is in full compliance with applicable standards,” the Joint Commission said.

The commission said that it had no indications of the problems in the brachytherapy program when it arrived at the hospital and that its surveys are not detailed enough to have uncovered the flawed implants.

I have previously written about the fact that medical errors happen at accredited hospitals. But for the same error to recur for six years says the accreditation system is flawed.

I was also struck by:

Susan Phillips, a senior executive at Penn’s medical school and health system, said Dr. Kao had voluntarily given up his clinical privileges there, though he continues to do research on campus.

Since it was shown that Dr. Kao falsified records during several brachytherapy procedures, why is he still doing research. Dr. Kao is listed as part of the clinical faculty of the University of Pennsylvania department of radiation oncology. The University of Pennsylvania is building a proton beam therapy (PBT) facility (scheduled to open in 2009) and will be the sixth such center to offer PBT treatment in the US.

What patients want

June 19, 2009

wantDB asked in his blog “When you consider physician quality, what attributes do you consider?” My response was:

  1. Unbiased treatment advice
  2. Physician knows more than I do

An ideal treatment is (at least in concept) effective with minimal side effects – cost is not an issue for insured patients. Yet, some physicians steer patients towards a treatment that may not be ideal for that patient – prostate cancer is one example. This leads to people using the internet and other sources to be their own patient advocate. Whereas it would be silly to think such research makes one competent, it is not good if one gets the feeling the doctor is not as knowledgeable as the patient.

Other responses were similar.

A Kano diagram is useful to frame the issue.



The green line is expected attributes. For example, if someone is going into a hospital for a total left hip replacement and the left hip is replaced (as opposed to the right hip), this is expected! It is not thought of as quality. Hence, there is no satisfaction for fulfilling this goal, only dissatisfaction if it is not fulfilled. This is similar to the airlines. One does not ask to review the maintenance records of a flight one is taking nor review the pilot’s resume. One expects these attributes to be in order.

The red line is also not specified. For example, if someone with a chronic condition was suddenly diagnosed and cured by a new doctor, this would be unexpected although of course there would be great value.

It is the blue line that is specified by patients. Take surgery for example. A famous urologist once said he would love to redo his first 100 prostatectomies. Surgery skill, notwithstanding the difficulty in getting this information is valued by patients. My and the other responses dealt with other attributes valued by patients.

I doubt if anyone would specify outcome measures such as “Percentage of patients who received advice to quit smoking” or any of the other 25 measures.

EP23 – Again

June 10, 2009

ep23-revThe title of EP 23 is Laboratory Quality Control Based on Risk Management. This title and hence the document makes no sense to me.

Risk management involves enumerating potential failure modes and implementing control measures for high risk failure modes. But quality control works whether one knows about failure modes or not. In fact, one of the values of quality control is precisely that one can know nothing about failure modes yet quality control will still detect failures.

Thus, Laboratory Quality Control is not Based on Risk Management would be a corrected title but also not a very good one.

There are many ways to go about setting up a quality control program – the Westgard site is a good place to start.

To illustrate things using the figure below, the outcome of a (highly abbreviated) risk management program is nevertheless an incorrect result. If QC succeeds, the incorrect result is suppressed.


Although one could talk about the total program as risk management, there is really no connection between trying to prevent or detect the many possible failure mode causes that can lead to an incorrect result and QC which detects (some) incorrect results regardless of the cause. And QC is not based on risk management.

Why you need to be your own patient advocate with lab tests

June 1, 2009

advocateLab tests have error and sometimes very large errors. As the last blog entry showed, patient harm can result from certain lab errors. In this blog entry, lab error means an error large enough to result in patient harm. But it is not the error itself that causes harm, it is the clinician acting on the result. When harm occurs from lab error, one can infer that the clinician has not questioned the accuracy of the test. Thus, it’s up to the patient to question the result.

Some examples of how lab results can have error:

Interferences – The HAMA interference from the previous blog is just one example of an interference and can occur on assays other than hCG.

Known bias  – Example: PSA values can differ by 22% on average depending on the manufacturer. This is due to how the assay is standardized. Say one’s PSA value was 3.3 as assayed by manufacturer ABC. If next year the assay value remained at 3.3 by manufacturer ABC, but a different manufacturer were used (that had this 22% different standardization), the reported value would be 4.0 on average. Actually, taking into account the ~5% CV of these assays, 95% of the time the value would be between 3.2 and 4.8 (e.g., half the time greater than 4). Unless questioned, this might lead to a biopsy. Often, the manufacturer is not listed on the lab report. To find this out, one must call the lab.

Problems with newer tests – Molecular testing with arrays is the newest type of testing. A recent article (subscription required for full article) showed that the reproducibility was often greater than 30% CV. If one translates this to a glucose test with a true value of 100 mg/dL, 95% of the time, values would be between 40 and 160 mg/dL! Another report showed that different generations of probe sets often had close to 0 correlation. Back to glucose, this is equivalent to running a method comparison between a newer and older machine and getting random scatter rather than a typical result of a correlation > 0.9.

Other problems – There are many other potential problems that would give an error such as a patient sample mix-up, an undetected instrument error, sample pretreatment problems, and so on.

When to question lab tests – In principle, any lab test could be questioned, although this could be (is) impractical. Moreover, the above problems will be unknown to patients not familiar with laboratory medicine and even people who are familiar with error causes may be unaware that an error has occurred.

Two scenarios are suggested to question lab tests:

  • Before a treatment is started, especially a treatment with risks such as surgery
  • If symptoms persist and a lab test was negative

How to question lab tests – Unfortunately, simply repeating a lab test will not always help. It depends on the error source. If the error source is random, then simply repeating the test will help. If the error source is not random, such as caused by an interference, then repeating the test by the same procedure in the same lab will not help. In situations with HAMA interference, part of the problem was that serial measurements gave the same wrong answers which prompted clinicians to continue (the wrong) treatment.

The safest way then is to request a test to be repeated by a different laboratory and preferably a reference laboratory, if one exists for that assay.

And remember – A wrong lab test is a rare event – whereas a result is worth questioning, the likelihood that a lab test is wrong is extremely low.

NO MEDICAL ADVICE: Material appearing here represents opinions offered by non-medically-trained laypersons. Comments shown here should NEVER be interpreted as specific medical advice and must be used only as background information when consulting with a qualified medical professional.