223333333q21Medical tests are an important first step in clinical management, whether they are routine blood pressure measurements, blood tests, imaging studies or more specialized investigations. 

69% of physicians believe that the average physician orders unnecessary medical tests and procedures at least once a week.

The overall aim of healthcare is to prevent premature morbidity and mortality.


The  value and rationale for performing tests lies in their ability to improve patient health outcomes by

detection and/or monitoring of disease and subsequent treatment. 


Health outcomes may be clinical, emotional, social, cognitive or behavioral.

Over-testing is at the root of many problems: Ordering, reviewing, and interpreting tests, explaining results, and follow-up testing consume valuable time.


As the gatekeepers to healthcare access physicians are ultimately responsible for requesting medical tests, making diagnoses and offering treatment and/or further tests, and are charged  with preventing overtesting.

When a test isn’t necessary, time can be more appropriately spent counseling patients, listening to them, and redoubling efforts to follow well-supported preventive guidelines.


Over-testing may be defined as the use of: 1) nonrecommended screening tests in asymptomatic patients, or 2) more testing than necessary to diagnose patients with signs or symptoms.


There are at least 5 reasons why clinicians over-test:


1) Belief that ordering many tests will help detect subclinical disease


2) Defensive medicine


3) Lack of knowledge or confidence


4) Patients’ expectations


5) Profit


When ordering unproven screening tests for asymptomatic patients without good reason, few consider the low yield, high cost per diagnosis made, and considerable toll of false positives.

Anecdotal accounts of unexpected diagnoses discovered on routine testing help perpetuate over-testing. 

Even the best tests yield more false positives than true positives when the prevalence of what one is testing for is low. 

Ordering tests to establish a baseline, but this has been shown repeatedly not to improve care for asymptomatic patients and consumes hundreds of millions of health care dollars per year.

Abnormal results that later prove erroneous engender unnecessary anxiety and needless follow-up testing. 

Overtesting, may cause harm to patients and the healthcare system:  misdiagnosis, false positives, false negatives and overdiagnosis. 


Clinicians are responsible for test requests, and are therefore ideally positioned to prevent overtesting and its unintended consequences. 


In a survey, 10% of physicians had incorrectly deemed positive predictive value to be the same between screening and diagnostic testing.

Testing may occur on the basis a sense of medical obligation driven by the clinician’s need to show that at least something was being done for the patient.


Overtesting of screening and diagnostic tests may occur where there is an unfavourable balance of benefits to harms exists: there being be little or no consequences to the patient from not performing the test.


Potential harms from overtesting: misdiagnosis, false positive results, false negative results and overdiagnosis, where people are labelled as having a disease for a condition that would not have caused them harm if it were left undetected and untreated.

Overtesting may initiate a further cascade of unnecessary investigations and treatment.

Overtesting may affect physical, , psychological  and financial interests.

Overtesting in the presence of finite healthcare resources prevents others from getting benefits  from tests, treatment and other interventions.

Overtesting consequences are increasingly proportional to the degree that it occurs.

Overtesting of monitoring tests may occur where the tests have poor measurement  value, and/or are done overly frequently.

Ordering only medically indicated tests reduces needless worry and, as an added benefit, helps lessen physicians’ workload.

Intrapersonal causes-fear of malpractice and litigation; clinician knowledge and understanding; intolerance of uncertainty and risk aversion; cognitive biases and experiences; sense of medical obligation.


Yet, malpractice concerns has not found to be a major driving factor for ordering tests.

Studies highlight unnecessary testing as a compensatory measure for lack of knowledge and understanding. 


Overtesting is related to lack of knowledge and understanding of the clinical process and drives  to understand the natural history of disease, and it’s appropriate management pathways. 

Greater cognizance of the drivers of overuse can positively impact clinical decision making and test ordering behavior.

The lack of knowledge and understanding of significance of test properties and results also encourages overtesting. 


Anxious patients more likely to request tests, and doctors conscious of long term relationships with patients were more likely to meet these requests. 

Physicians are more likely to acquiesce to patient demands for tests if patients threatened to see another clinician. 

The better the relationship between doctor and patient, the less likely patients were to demand unnecessary tests, and the less likely doctors would be to order unnecessary tests.

Among the commonest reasons for ordering low value tests were desire to reduce uncertainty (84%) and just to be safe (78%).

The shotgun approach of ordering a broad range of tests and hoping for a positive result  is often used in situations of diagnostic uncertainty. 

There is a positive correlation between likelihood of ordering imaging tests and level of litigation concern.

A survey of United States (US) emergency physicians found 97% of respondents ordered advanced imaging tests due to fear of litigation and missing a low probability diagnosis despite feeling the tests were unnecessary. 


Physicians with greater levels of anticipated regret in missing serious disease were more likely to recommend testing.

Unnecessary testing often occurs as a result of cognitive biases being  associated with the impact of previous experience of clinical events.  

Physicians  with recent negative clinical,experiences are more likely to adopt an aggressive approach to diagnostic testing.

Also  a positive experiences from test ordering can increase the likelihood of ordering further tests in the future.

The overinterpretation of positive results, makes clinicians are more likely to order further tests. 

Pathologists concerned about litigation have lower implicit disease thresholds for indeterminate and malignant tumor diagnoses. 


Interpersonal causes-pressure from patients and doctor-patient relationship; pressure from colleagues and medical culture.


Environment/context– guidelines, protocols and policies; financial incentives and ownership of tests; time constraints, physical vulnerabilities and language barriers; availability and ease of access to tests; pre-emptive testing to facilitate subsequent care; contemporary medical practice and new technology.


Financial incentives and ownership of testing results in more tests being performed, as well as remuneration on a larger scale. 

Physician induced demand occurs when physicians can order return visits and perform diagnostic tests when indications are vague or controversial. 


Physicians  working in private healthcare settings are more likely to be driven by economic incentives in regards to test ordering. 

Physicians who own imaging equipment engage in more testing with similar clinical outcomes: a financial conflict of interest as a driver of overtesting. 

Pressure from other clinicians may drive unnecessary testing: one study  found that as many as 89.6% of physicians would order a screening test they would not have otherwise ordered if specialists had recommended the test.


Guidelines, protocols and policies have a significantly influence over test ordering behavior.



Non-existent or discordant guidelines can result in overtesting.


Defensive medicine’s role in over-testing is well established. 


Tests done without improving health outcomes, may be examples of overtesting. 

Overtesting includes unnecessary medical testing does not improve clinical decision making, or health outcomes.

Ninety-one percent of physicians surveyed recently reported ordering more tests or procedures than needed to protect themselves from malpractice suits.

Harvard School of Public Health study indicates that this accounts for a substantial proportion of our nation’s $55 billion malpractice costs annually. 

Ordering more tests doesn’t buy protection; indeed, failure to follow up on results creates almost as many medicolegal problems as failure to diagnose.


Over-testing is often learned in training, either during an era when more is better had no evidence to refute it, or from a mentor who trained in such an era.

Some training programs have begun placing increased emphasis on the importance of judicious testing.

Lack of knowledge or confidence are other potentially remedial contributors to over-testing, and are often intertwined: deficits exist in individual knowledge, it can feel more reassuring to order batteries of tests than to fill the knowledge gaps. 

A major contributor to over-testing is profit motive. 

The odds of ordering common laboratory tests are up to 8 times higher among physicians with financial stakes in an on-site laboratory, even after adjusting for patient and practice differences.


Patient expectation also leads to over-testing: expecting panels of tests at regular intervals. 

Physicians may worry that a patient’s satisfaction depends upon ordering many tests. 

Ordering tests, is often easier than explaining reasons behind not doing so, but the choice is between good medicine and easy medicine. 

Preoperative testing is an example of the roles defensive medicine and lack of knowledge play in over-testing: requests for panels of laboratory tests preceding minor outpatient procedures, as well as chest radiographs and electrocardiograms that don’t appear to take into account the type of surgery, patient’s age, or history. 

Patients without respiratory problems don’t need preoperative chest radiographs unless thoracic or upper abdominal surgery is scheduled. 

Except where medical history dictates otherwise,

Cataract surgery, arthroscopies, and other relatively bloodless procedures require no preoperative laboratory testing.

Fear of a cancelled procedure often leads to overtesting requests.

Individual clinicians should: Refrain from ordering baseline or screening tests on patients who otherwise have no medical indication. 2) Refrain from ordering preoperative tests that do not make medical sense 3) Becoming  familiar with evidence-based guidelines and use them to guide testing: Choosing Wisely campaign, a partnership of the American Board of Internal Medicine and more than 50 specialty societies. 4) Share with your patients your reasons for avoiding over-testing.


Time pressures in the work environment limits time with patients and encourages physicians to provide a test just to expedite the clinical encounter.

Tests are more likely to be ordered when logistically easier: day shifts vs nights, when in closer proximity of testing sites, presence was little resistance in test ordering, or when able to order from desktop devices.

Wait times and patient physical mobility affected likelihood of echocardiogram test ordering. 

Having the available technology and equipment is also a key predictor of testing ordering.

Contemporary medical practice with emphasis and even reliance on technical tests with a relatively lower priority given to history taking and physical examination, contributes to overtesting.

The improved radiology  techniques and interpretation is a major cause of overall increased investigation volume that is frequently unnecessary.

Patients may have unrealistic or ill-informed expectations of testing. 

Medical education that instils fear of uncertainty encourages overtesting. 

Physicians have the ability and responsibility to limit overtesting and to prevent harm to patients and the healthcare system. 




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