In medicine, as patients we would like there to be black and white answers. Either are tests are positive or negative or there is a problem or there is not. Unfortunately, sometimes medicine resembles life, and there are shades of gray with medical testing or diagnosis.

Whenever medical testing is done there are at least 3 components that may influence your results. It’s important for you to recognize this otherwise, you may always think that lab tests or their interpretation are infallible and this is not the case.


The Validity of Your Test Results is influenced by at least the following three elements

1) The quality of the equipment used and type of testing
For example, there are different types of mammograms and different machines used. Digital mammograms have been found to be better at detecing cancer in women with dense breast tissue vs film mammography. Therefore sometimes film mammography may show no abnormalities on a mammogram whereas digital mammography may show some areas of concern.

Another example, is that MRI Machines or Magnetic Resonance Imaging Machines have different “resolutions” — the higher the resolution, the easier it is for radiologists to detect certain abnormalities. Kathy M, a patient with a brain tumor, traveled out of state for her surgery, and each year she must travel out of state to have her follow up MRI scans done at the same University setting and using the same MRI machine because it is important for her neurosurgeon to compare her scans using the same quality and type of machine and the only way for him to do that is to have his patient be re-scanned each year using the same equipment. So having an MRI scan done at either two different hospitals or facilities may not give you the same results in terms of findings.

2) The expertise of the person reading the scan or result
Always keep in mind that when dealing with medicine, you are dealing with “opinions”. Generally, we are dealing with health care professionals who specialize in a particular area and who are educated about particular areas of health and disease, but nontheless it is important to realize that intrepretation of some test results is an “art” as well as a “science” and it is just an “opinion” of the medical person who is reading or intrepreting those test results for us.

For example, A patient in her 40’s received a mammogram after finding a lump in her right breast, from a radiological practice that was one of the largest providers of outpatient imaging in her home state of Texas. The mammogram report discussed the mass in the right breast, but said the left breast was “unremarkable” except for dense breast tissue.

An ultrasound was done on the right breast, and the radiology report from the reading radiologist said that the mass was “probably benign” and recommended that the patient return in 6 months for a follow up ultrasound test. The patient’s local physician decided not to “wait for another six months” and sent the patient to a well respected breast surgeon in the area, who reviewed the mammogram and ultrasound and decided that the patient needed a breast biopsy on the right breast. The breast surgeon did not mention anything about the left breast and discussed biopsy options with the patient. Because the patient was scheduled to travel out of state to receive some other specialized medical care for another issue at one of the most well known medical facilities in the country she opted to get a 2nd opinion at the other medical center a few days later. Interestingly enough, the radiologist reviewing the patient’s medical records at the out-of-state medical center said not only did the patient have a mass in the right breast, but she had a mass in the left breast as well, but the left breast mass was potentially even more concerning that the mass identified in the right breast.

In our next segment, we’ll give you the rest of the details about this patient’s testing and results, and will finish up by giving you the 3rd element that’s always important to consider when you as a patient evaluate the validity of your medical testing.