Now that prospective payment has imposed limits on consumption of
laboratory resources, inappropriate test utilization by clinicians can
represent a serious dollar drain. Microbiology, one of the
laboratory’s least automated and most labor-intensive areas, is
particularly liable to incur financial losses from excessive test
The main problem laboratories face is inappropriate utilization by
clinicians. In the not too distant past, underutilization of the
microbiology laboratory was common. A recent requirement by the Joint
Commission on Accreditation of Hospitals for some form of audit of
antibiotic usage has led most hospitals to require that appropriate
cultures be taken, so underutilization is becoming less of a problem.
Clinical laboratory services are very susceptible to
overutilization, however. Since hospitals will no longer be reimbursed
for the cost of each laboratory test under prospective payment,
excessive laboratory usage can very easily result in a significant loss
of funds in many patient admissions.
An example of overuse is the ordering of differential counts.
Shapiro et al analyzed the use of differential counts in a 700-bed
university teaching hospital and found that 26 per cent of all
differentials done in the hospital laboratory were unjustified.
Forty-eight per cent came from medical services, 62 per cent from
surgical services. The test results affected patient management in less
than 3 per cent of patients, and no unjustified tests altered a
patient’s diagnosis or treatment. Elimination of unjustified
differentials would permit a reduction in 1.8 FTEs from their hospital
laboratory. It was concluded that the differential is overused and
amenable to real cost reduction.
Because of the lack of automation presently available to the
clinical microbiology laboratory, there is a direct relationship between
the workload and the number of technologists needed. Technologists’
salaries account for 50 to 70 per cent of a laboratory’s
microbiology is an expensive laboratory service. It has been noted that
repetitive, often daily cultures from infected foci clearly reflect
concern on the part of the physician but contribute little or nothing to
patient care. Examples of this overuse include excessive numbers of
blood cultures, daily sputum cultures from tracheostomized patients
without evidence of pneumonia, daily cultures of drainage from infected
foci, and Foley catheter tip cultures.
A study at one hospital revealed that the average patient had 6.1
bacteriology tests per admission. Some patients had as many as 122
bacteriology tests, including up to 24 urine cultures. A typical
pulmonary patient in this study had an average of 16 sputum cultures, 13
blood cultures, and 9 urine cultures!
To promote the optimal use of laboratory tests, we must consider
not only factors responsible for inappropriate or excessive use, but
also those that foster underuse. The latter include failure to review
test results and inability to interpret them. Optimizing laboratory
utilization requires explicit criteria regarding when laboratory tests
should be used and development of methods to insure that the resulting
data are utilized properly.
To be appropriate, a test should affect a patient management
decision. In microbiology, this primarily occurs through demonstration
and identification of microorganisms and determination of their
The process usually involves genus identification and
susceptibility testing and/or precise identification to species or
subspecies level. For most physicians, the former has a greater
priority than precise identification.
Besides providing information clinical requirements. Examples of
this would include the typing of Haemophilus influenzae other than b,
typing of Neisseria meningitidis and Klebsiella pneumoniae, and the
species identification of yeast from mixed cultures.
Specimens of dubious value such as those from mouth lesions, bowel
contents, perirectal abscesses, decubiti, vaginal discharges, and Foley
catheter tips should not be processed. It is not clinically helpful to
provide complete identification and antibiotic susceptibilities of more
than three pathogens in a specimen. Recovery of three or more pathogens
generally reflects contamination of the specimen with indigenous flora.
Concerned over the possible misuse of laboratory services, the
state of Connecticut in 1975 formed an ad hoc committee of clinical
microbiologists and pathologists to investigate the utilization of
microbiology laboratories. Two years later, the College of American
Pathologists convened a meeting in which infectious disease specialists,
pediatricians, surgeons, and other physicians met with clinical
microbiologists and pathologists to consider clinical relevance in
The findings and recommendations of both meetings were strikingly
similar. There was a recommendation that institutions establish a
policy for controlling laboratory utilization.
Cost containment measures in medical practice will not be
successful if they are initiated by administrative fiat. Conscientious
physicians will rebel against constraints they see as deleterious to
patient care. Demonstrating what is useful, as opposed to what is
unnecessary or harmful, is the cornerstone of scientific medicine.
While it is desirable that physicians know the sensitivity, specificity,
and predictive values of laboratory tests, they cannot know the
performance characteristics of all the tests they order. To minimize
inefficient and ineffective practice, it is essential that clinicians
and laboratory directors develop guidelines for testing.
The laboratory director should submit specific recommendations to
the directors of the clinical services for their input. When agreement
has been reached, the decisions should be approved by the medical board
and incorporated into hospital policy by the administration. All
attending physicians and the house staff should then be advised of the
new laboratory policies and assured that appropriate exceptions can be
made by consulting with the laboratory director. The active
participation of the chiefs of service through chart review is also
important for the success of cost containment programs.
Clinical laboratories can contribute further to improving the use
of tests. Laboratory request forms need to be examined. Forms that
list the entire inventory of available tests are an open invitation to
the user to check off excessive numbers of tests. Active intervention
to reinforce an educational program may be required to overcome
established patterns of misuse of laboratory resources.
Specific strategies for cost containment include the following:
1. Have as much testing done as possible on an outpatient basis,
preadmission and post-discharge. This reduces length of stay and
removes some testing from prospective payment limits.
2. Revise laboratory request forms that list tests or procedures by
check-off boxes. Provide a separate menu that lists specific tests.
For example, when submitting female genital specimens, physicians should
state whether they are for possible gonorrhea, vaginitis, surgical wound
infection, or possible endometritis.
3. Attempt to shorten turnaround time through faster ways of
getting the specimen to the laboratory, testing it, and delivering the
results. Stat tests are disastrous from the perspective of laboratory
efficiency and cost control, but are often necessary from a medical
Many Stats can be avoided, however, by better routine scheduling
and establishing priority of tests based upon clinical urgency. A
procedure assigning priority to microbiology specimens based upon their
relevance to the urgency of the clinical problem has been described by
Ellner et al. Reorganize the laboratory into Stat and routine sections
to improve productivity.
4. Eliminate tests that are unnecessry–i. e., that do not
contribute to the patient’s diagnosis, management, or prognosis.
Typical examples of these are throat cultures for organisms other than
beta hemolytic streptococci; identification of more than three pathogens
in a specimen; cultures of oropharyngeal material, bowel contents,
perirectal abscesses, decubiti, and Foley catheter tips, and anaerobic culture of surface wounds; and antibiotic susceptibility determinations
on obvious contaminants, commensal species from sites they normally
inhabit, or species with predictable susceptibilities.
5. Curb ordering of esoteric tests, and require the prior approval
of an infectious disease specialist. An example is the culture of
cerebrospinal fluid for acid-fast bacilli.
6. Eliminate replicate and redundant specimens by computer
monitoring at registration. The laboratory cannot afford to perform
three cultures on the same wound because an intern, a resident, and the
attending physician all ordered one independently on the same day.
7. Eliminate tests done by standing orders or routine protocol.
Typical examples are tracheal suction specimens from patients in the
intensive care unit with no clinical evidence of pneumonia, and
peritoneal dialysis specimens from patients with no signs of
8. Limit the maximum number of specimens of each type that will be
accepted from a patient. Some suggestions are shown in Figure I.
9. Develop progressive test profiling, in which follow-up tests are
automatically performed according to predetermined, cost-efficient
algorithms designed to obtain the most diagnostic information. Examples
are the testing of serum for syphilis, hepatitis, or streptococcal antibodies.
The laboratory can contribute to the more cost-effective use of
antibiotics by selective reporting. In our institution,
second-generation cephalosporin results are reported only if the
organism is resistant to cefazolin, and third-generation drugs are
reported only if the isolate is resistant to both cefoxitin and
10. Eliminate routine environmental cultures. These include
samples from floors, surfaces, air, presterilized fluids, medications,
or infant formula milk.
11. Cut total costs by sharing lab services and resources with
other hospitals. Economies of scale result from this approach.
12. Increase test volume from sources outside the hospital to
compensate for cuts in inpatient volume, and adopt competitive
outpatient pricing. Fixed laboratory costs remain the same. The added
business will entail only variable-cost increases.