The Impact of Requisition Design on Laboratory Utilization

Clinical Chemistry / LABORATORY REQUISITIONS AND UTILIZATION
<strong>The</strong> <strong>Impact</strong> <strong>of</strong> <strong>Requisition</strong> <strong>Design</strong> on Laboratory Utilization
Jane F. Emerson, MD, PhD, 1 and Scott S. Emerson, MD, PhD 2
Key Words: Laboratory utilization; <strong>Requisition</strong>; Panels; Medical necessity; Cascade
Abstract
Laboratory utilization by clinician specialty groups
serving outpatients was monitored before and after
requisition redesign. <strong>Requisition</strong> changes were designed
to address compliance and utilization issues and
included implementation <strong>of</strong> test groupings and cascades
or ordering algorithms. Data collected included the
number <strong>of</strong> selected tests and test sets ordered during
both time intervals and the number <strong>of</strong> patient <strong>of</strong>fice
visits. Selected tests for monitoring included CBC
counts, metabolic panels, thyroid function tests, hepatic
function tests, urine analysis, and send-out testing.
Statistical significance was measured using Poisson
rates for test ordering. <strong>The</strong> composite effect was a
significant decrease in the overall number <strong>of</strong> tests
ordered per outpatient visit for most specialties, with a
shift in ordering practices from panels to individual
tests. Utilization rates by specialty groups were
characterized by average number <strong>of</strong> laboratory tests
ordered per patient visit.
© American Society <strong>of</strong> Clinical Pathologists
Increasingly, regulatory and institutional pressures are
shifting the burden <strong>of</strong> ensuring the medical necessity <strong>of</strong> laboratory
tests to the clinical laboratory itself. In response, the clinical
role <strong>of</strong> the pathologist in laboratory medicine has
expanded from providing consultation on an as-requested basis
to one that entails proactive and widespread guidance to clinicians
in test ordering. One method <strong>of</strong> dealing with these educational
and operational challenges is to alter the format and
content <strong>of</strong> the information that is exchanged routinely between
the clinician and the laboratory. 1-4 In most cases, the laboratory
requisition, whether on paper or on a computer screen, serves
as an obligatory interface in the process. It is recognized as
such by the Office <strong>of</strong> the Inspector General <strong>of</strong> the Department
<strong>of</strong> Justice and, hence, is regulated strictly. 5 At the University <strong>of</strong>
California–Irvine Medical Center, Orange, the clinical laboratory
undertook the project <strong>of</strong> redesigning laboratory requisitions
to achieve the dual goals <strong>of</strong> ensuring compliance with all
applicable regulations and to significantly influence test utilization.
In an academic medical center setting in which the laboratory
serves physicians at various levels <strong>of</strong> training and experience,
a requisition providing information either explicitly or
implicitly serves as an educational tool. This study was a quantitative
assessment <strong>of</strong> the impact <strong>of</strong> requisition design on physician
ordering practices in the outpatient setting.
Materials and Methods
Baseline Data
To determine baseline ordering practices, the number <strong>of</strong>
all laboratory tests ordered by physicians in each outpatient
location was retrieved from the laboratory information system
Am J Clin Pathol 2001;116:879-884 879

Emerson and Emerson / LABORATORY REQUISITIONS AND UTILIZATION
LIVER / GI
X
Screen for liver disease/cholestasis
ALT 84460
Alkaline phosphatase 84075
Bilirubin 82247
Conjugated bilirubin
Biliary obstruction
82248
GGT
Chronic liver disease
82977
Total protein 84155
Albumin 82040
PT
Viral hepatitis, acute
85610
HAV antibody, lgM 86709
HCV antibody 86803
HBSAg 87340
HBCoreAB, IgM 86705
HCV, PCR
Viral hepatitis, chronic
87521
HBSAg 87340
HCV antibody
Pancreas
86803
Amylase 82150
Lipase 83690
Triglycerides 84478
Calcium 82310
Glucose
Malabsorption
82947
Fecal fat
Infectious diarrhea
82710
Stool culture, rule out enterics 87045
Ova / parasites X3
(3 consecutive days)
MULT
❚Figure 1❚ An extract <strong>of</strong> the requisition used for the Family
Medicine group. All tests are ordered individually. Current
Procedural Terminology codes are displayed to the right <strong>of</strong>
the test names. Laboratory test codes (not shown) also are
present on the requisition. ALT, alanine aminotransferase;
GGT, gamma-glutamyltransferase; GI, gastrointestinal; HAV,
hepatitis A virus; HBCoreAb, hepatitis B core antibody;
HBSAg, hepatitis B surface antigen; HCV, hepatitis C virus;
MULT, multiple; PCR, polymerase chain reaction; PT,
prothrombin time.
(LIS) for a period <strong>of</strong> 6 months on a calendar year-to-date basis
(January through June). Tests were ordered by residents or
attending staff. <strong>The</strong> data format from the LIS is in the form <strong>of</strong>
numbers <strong>of</strong> each test code ordered during a given period per
patient location code (or point <strong>of</strong> service). By test code count, a
comprehensive metabolic panel and a single sodium measurement
each count as one test. <strong>The</strong> data from multiple patient
location codes then were grouped manually to result in the
number <strong>of</strong> tests ordered per specialty. <strong>The</strong> number <strong>of</strong> patient
<strong>of</strong>fice visits to each location during the same interval was
obtained independently through the use <strong>of</strong> reports from the
medical center’s registration and billing information system.
<strong>Requisition</strong> <strong>Design</strong> and Implementation
New laboratory requisitions were constructed to include
multiple features designed to satisfy compliance, utilization,
and educational goals. To be in compliance with regulations,
key patient demographic and diagnostic information fields
were clearly marked as requisite for specimen processing. A
statement attesting to medical necessity <strong>of</strong> ordered tests
signed by the ordering physician was included. Previously
existing panels <strong>of</strong> tests were dissolved with only Medicareapproved
panels remaining. To encourage ordering <strong>of</strong> only
medically indicated tests, approved panels were also deemphasized
by locating them on the requisitions in less
prominent positions. Reflexive testing and the components
<strong>of</strong> all panels or cascades were described clearly on the front
<strong>of</strong> the ordering form. Although not required to be part <strong>of</strong> the
laboratory requisition, a complete advance beneficiary notice
(ABN) was included on the laboratory form as an aid to
physicians to be in compliance with Medicare regulations.
Current Procedural Terminology codes are displayed for
each orderable test or panel.
To influence utilization and accomplish educational
objectives, requisitions were customized to groups <strong>of</strong>
specialties and patient service locations with common
ordering practices based on an analysis <strong>of</strong> the baseline data.
Tests were grouped by organ, disease, or specialty with
subgroupings <strong>of</strong> tests defined by headers to guide in test
selection. Specific test groupings were decided in consultation
with appropriate physician specialists. An extract <strong>of</strong> the
requisition used for Family Medicine is displayed in ❚Figure
1❚. Under the heading entitled Liver/GI, subheadings serve to
guide test selection for common clinical manifestations.
<strong>The</strong>se test groupings obviated the need for customized
panels that have been criticized as compromising physician
choice. This approach resulted in some cases in duplication
<strong>of</strong> tests that would be included in more than one major category;
for example, prothrombin time is included in the
Liver/GI section (Figure 1) under the header “Chronic liver
disease” and is also included in the “Coagulation” section <strong>of</strong>
the requisition (not shown).
Several cascades were implemented or emphasized with
the aim to ensure medical necessity <strong>of</strong> tests while preserving
minimum time to diagnosis and convenience for both clinicians
and patients. A thyroid cascade, a urine screen for
culture, and an anemia cascade were included on requisitions
for most specialties. <strong>The</strong> anemia cascade ❚Figure 2❚ was
designed such that whole blood and serum specimens would
be obtained at the outset. Hemoglobin and hematocrit values
880 Am J Clin Pathol 2001;116:879-884 © American Society <strong>of</strong> Clinical Pathologists

Hemoglobin
and
hematocrit
Either result low Otherwise
Measure RBC indices Stop
Normocytic Microcytic Macrocytic
Reticulocyte
count
Antiglobulin
would be determined from the whole blood specimen, and if
results were normal, no further testing would be performed.
If the hemoglobin and hematocrit results indicated anemia,
RBC indices would be used to determine the subsequent
workup needed by using the specimens initially collected.
<strong>The</strong> extent <strong>of</strong> the laboratory’s complete test menu
presented on the requisitions was limited to include only the
laboratory tests that typically are indicated clinically.
Preserving the efficiency <strong>of</strong> laboratory operations, however,
dictated that the number <strong>of</strong> write-in tests be kept at a
minimum, since these <strong>of</strong>ten are subject to misinterpretation,
and verbal verification has been shown to contribute to error
rates. 6 Using baseline ordering data, it was decided to
include all laboratory tests that were ordered with a
frequency <strong>of</strong> once per month or more for each specialty
group. For the majority <strong>of</strong> tests ordered then, the physician’s
intent is clarified by the presence <strong>of</strong> both the Current Procedural
Terminology codes and internal laboratory test codes
for each orderable entity. Blank fields for write-in requests
were included at the bottom <strong>of</strong> each requisition.
Clinicians were oriented to the new requisitions by
presentations at medical staff meetings and by laboratory
staff performing clinic “walk-throughs.” <strong>The</strong> requisitions
were in place in the clinics and in use for a period <strong>of</strong> 6
months before follow-up data collection began.
© American Society <strong>of</strong> Clinical Pathologists
Iron studies B 12 folate
❚Figure 2❚ <strong>The</strong> anemia cascade is designed to screen for and
diagnose common anemias. Both blood and serum
specimens are collected initially; the serum is not used if no
anemia is found.
Clinical Chemistry / ORIGINAL ARTICLE
Follow-up Data and Data Analysis
Monthly data from the LIS were collected as described
for a period <strong>of</strong> 7 months (calendar year-to-date with data
collection at the end <strong>of</strong> July). For each test or test set, the SD
from the mean <strong>of</strong> the monthly data was used to estimate the
variability in the ordering practices for each location for the
2 time intervals. <strong>The</strong> total number <strong>of</strong> laboratory tests ordered
by specialty was divided by the number <strong>of</strong> patient-<strong>of</strong>fice
visits per specialty to obtain the number <strong>of</strong> tests normalized
by patient volumes.
Data monitoring and analysis targeted total tests
ordered, number <strong>of</strong> panels ordered, and selected disease- or
organ-specific testing. <strong>The</strong>se included hepatic function
testing, thyroid function testing, urine analysis and cultures,
metabolic panels, lipid pr<strong>of</strong>iles, basic hematology, and the
total number <strong>of</strong> tests ordered that were not performed inhouse
but were sent to reference laboratories (send-out tests).
As is common when measuring counts <strong>of</strong> events, a
Poisson distribution was assumed for the number <strong>of</strong> tests
ordered. 7 Statistical significance was based on a test <strong>of</strong> means
using the Poisson variance relationship in the test statistic.
Results
Baseline ordering practices and certain operational
aspects within the outpatient clinics (which may be medical
center–specific) led to combining individual specialties into
7 groups for the purposes <strong>of</strong> customizing laboratory requisitions
❚Table 1❚. In addition to the primary requisition, an
additional requisition for comprehensive infectious disease
testing was made available to each <strong>of</strong> the clinical sites.
Baseline month-to-month variability for the total number
<strong>of</strong> laboratory tests ordered by all specialty groups as
measured by coefficient <strong>of</strong> variation was 6%. Per test, the
coefficients <strong>of</strong> variation for the baseline ordering ranged from
4% to 14% (mean, 7%; SD, 3%), with the highest variability
corresponding to tests sent out to reference laboratories.
<strong>The</strong> specialties that were the highest users <strong>of</strong> laboratory
testing as measured by total number <strong>of</strong> tests ordered during
the periods <strong>of</strong> data monitoring are shown in ❚Figure 3❚.
Internal medicine, the outpatient cancer center clinics, and
family medicine together accounted for the majority (64%)
<strong>of</strong> the laboratory tests ordered.
For the 2 time intervals, ❚Figure 4❚ displays the total
number <strong>of</strong> tests ordered by all locations, the number <strong>of</strong>
patient <strong>of</strong>fice visits, and the number <strong>of</strong> tests ordered normalized
by <strong>of</strong>fice visits. <strong>The</strong>re was no significant change in the
total number <strong>of</strong> laboratory tests ordered, while the number <strong>of</strong>
patients seen in the outpatient clinics increased by 20%. <strong>The</strong>
normalized test ordering decreased beyond the baseline
month-to-month variability after implementation <strong>of</strong> the new
Am J Clin Pathol 2001;116:879-884 881

Emerson and Emerson / LABORATORY REQUISITIONS AND UTILIZATION
❚Table 1❚
<strong>Requisition</strong> Types *
Family Medicine
Family medicine
Geriatrics
Pediatrics
General pediatrics
Pediatric subspecialties
Internal Medicine and Subspecialties
Internal medicine
Dermatology
Neurology
Endocrinology
Cardiology
Gastroenterology
Nephrology
Surgery
Surgical specialties
Cancer center
Dialysis
Transplant clinics
Medical Subspecialties
Allergy
Immunology
Rheumatology
Obstetrics and Gynecology
Obstetrics
Gynecology
Infectious Disease
Infectious disease
HIV/AIDS
* Specialties and clinics were grouped by ordering practices as measured by baseline
data acquisition described in the text. Each group listed uses 1 customized
requisition.
20,000
18,000
16,000
14,000
12,000
10,000
8,000
6,000
4,000
2,000
0
Int Med Cancer Fam Neur Peds Transpl Renal Endo Rheu GI AIDS Card Inf Dis Ortho Otol Urol Derm
❚Figure 3❚ <strong>The</strong> total number <strong>of</strong> laboratory tests ordered by
specialty during the baseline period (left bars) and after the
requisitions were changed (right bars). <strong>The</strong> error bars
represent month-to-month variability in test ordering. <strong>The</strong>
number <strong>of</strong> patients seen in all specialties increased by an
average <strong>of</strong> 20%; the data are not normalized to patient <strong>of</strong>fice
visits. Cancer, all outpatient locations in the Cancer Center;
Card, cardiology; Derm, dermatology; Endo, endocrinology;
Fam, family medicine; GI, gastroenterology; Inf Dis,
infectious disease; Int Med, internal medicine; Neur,
neurology; Ortho, orthopedics; Otol, otolaryngology; Peds,
pediatrics; Renal, nephrology; Rheu, rheumatology; Transpl,
transplantation; Urol, urology.
❚Figure 4❚ Laboratory tests ordered (Labs) and patient visits
for all specialties. Left bars indicate data obtained during the
baseline period; right bars represent data obtained during
the second time period. Error bars represent variability in
test ordering practices as measured by the SD <strong>of</strong> the
monthly data. <strong>The</strong> total number <strong>of</strong> laboratory tests ordered
did not change significantly, while the number <strong>of</strong> tests
ordered per visit decreased significantly (P < .01).
requisitions. As measured by Poisson rates, overall utilization
<strong>of</strong> laboratory testing decreased significantly (P < .01).
Laboratory tests per patient-<strong>of</strong>fice visit are shown in
❚Figure 5❚. <strong>The</strong> highest users were in the transplant clinics
with typical orders <strong>of</strong> 2 or 3 tests per visit, while medical
specialties and the cancer center ordered 1 to 1.5 tests per
visit. Of the primary care specialties, pediatrics used laboratory
services the least, with only 1 in 3 <strong>of</strong>fice visits resulting
in test ordering. By Poisson rates, all specialties showed a
significant (P < .01) reduction in laboratory utilization with
882 Am J Clin Pathol 2001;116:879-884 © American Society <strong>of</strong> Clinical Pathologists
1.6
1.4
1.2
1.0
0.8
0.6
0.4
0.2
0.0
3.50
3.00
2.50
2.00
1.50
1.00
0.50
Total Labs (10 5 ) Total Visits (10 5 ) Labs/Visits
0.00
Int Med Cancer Fam Neur Peds Transpl Renal Endo Rheu GI AIDS Card Inf Dis Ortho Otol Urol Derm
❚Figure 5❚ <strong>The</strong> number <strong>of</strong> laboratory tests ordered per patient
visit for each specialty for the time periods before (left bars)
and after (right bars) implementation <strong>of</strong> redesigned
requisitions. Error bars represent variability in test ordering
practices as measured by the SD <strong>of</strong> the monthly data. <strong>The</strong>re
was a significant decrease (P < .01) in number ordered for all
groups except neurology, AIDS, GI, urology, and orthopedics.
See Figure 3 for an explanation <strong>of</strong> the abbreviations.

A B
18,000
16,000
14,000
12,000
10,000
8,000
6,000
4,000
2,000
0
Basic Metabolic Panel Comprehensive Metabolic Panel Total Metabolic Panels
C D
8,000
7,000
6,000
5,000
4,000
3,000
2,000
1,000
© American Society <strong>of</strong> Clinical Pathologists
25,000
20,000
15,000
10,000
5,000
0
Clinical Chemistry / ORIGINAL ARTICLE
CBC With Differential CBC Without Differential Total CBCs Anemia Cascade Hemoglobin and
Hematocrit
0
0
Urine Analysis Urine Culture Screen for Culture
TSH Free T4 Total T4 Total T3 FTI/T3UP Thyroid Cascade Combined TSH
and Cascade
❚Figure 6❚ Data in each graph compare tests ordered by all
specialties during the baseline monitoring period (left bars) with
the number <strong>of</strong> tests ordered for a comparable time period after
implementing requisition changes (right bars). Error bars
represent variability in test ordering practices as measured by
the SD <strong>of</strong> the monthly data. A, <strong>The</strong>re was a significant decline
(P < .01) in the number <strong>of</strong> basic and combined metabolic
(chemistry) panels ordered. B, Significant decreases (P < .01)
were noted for the total number <strong>of</strong> CBC counts ordered and for
the number <strong>of</strong> CBC counts without differential. <strong>The</strong> number <strong>of</strong>
CBC counts with differential increased significantly. <strong>The</strong> option
for CBC without differential was inadvertently omitted from the
Family Medicine requisition. C, While the use <strong>of</strong> the urine
screen for culture increased significantly, the number <strong>of</strong> urine
analyses and urine cultures significantly decreased (all P < .01).
D, All thyroid function testing decreased significantly (P < .01)
with a shift toward free T 4 and the thyroid cascade. E,
Combined hepatic testing and orders for the hepatic function
panel decreased significantly (P < .01). <strong>The</strong>re was a significant
increase in the number <strong>of</strong> individual analytes ordered with the
6,000
5,000
4,000
3,000
2,000
1,000
E
10,000
9,000
8,000
7,000
6,000
5,000
4,000
3,000
2,000
1,000
0
Hepatic Function
Panel
Alkaline
Phosphatase
GGT AST ALT Combined
Hepatic Function
exception <strong>of</strong> ALT. ALT, alanine aminotransferase; AST, aspartate
aminotransferase; FTI/T 3 UP, free thyroxine index/T 3 uptake; GGT,
gamma-glutamyltransferase; T 3 , triiodothyronine; T 4 , thyroxine;
TSH, thyrotropin (thyroid-stimulating hormone).
Am J Clin Pathol 2001;116:879-884 883

Emerson and Emerson / LABORATORY REQUISITIONS AND UTILIZATION
the exception <strong>of</strong> neurology and AIDS (significant increase)
and gastrointestinal service, urology, and orthopedics (no
significant change).
Evidence <strong>of</strong> changes in ordering practice for outpatients
is shown in ❚Figure 6❚. <strong>The</strong> total number <strong>of</strong> metabolic panels
decreased significantly (P < .01) for the second time period.
<strong>The</strong>re was no significant change in the ratio <strong>of</strong> comprehensive
to basic metabolic panels ordered. Basic hematology
ordering practices changed in that there was a significant
decrease in the total number <strong>of</strong> CBC counts ordered. <strong>The</strong>
number <strong>of</strong> CBC counts with differential increased significantly.
This may be partially attributed to the fact that on one
<strong>of</strong> the requisitions serving a high-utilizing group <strong>of</strong> specialties,
the option <strong>of</strong> ordering the CBC without differential was
inadvertently omitted. Overall orders for urine analysis and
urine cultures declined significantly. <strong>The</strong> “Screen for
Culture” cascade for urinalysis, which is followed by culture
conditioned on urinalysis findings, was ordered 10-fold more
frequently during the second interval. In thyroid function
testing, the combined orders <strong>of</strong> thyrotropin and the thyroid
cascade decreased in response to requisition changes. <strong>The</strong>
pattern <strong>of</strong> ordering, measured as a percentage <strong>of</strong> total thyroid
function testing, shifted toward thyrotropin, free thyroxine
(T 4 ), and the thyroid cascade and away from total T 4 , total
triiodothyronine (T 3 ), and free thyroxine index or T 3 uptake.
For the latter 2 tests, ordering virtually disappeared, with
only a few write-in requests remaining. <strong>Requisition</strong> design
had a dramatic impact on the pattern <strong>of</strong> testing used to
address liver disease. <strong>The</strong>re was a significant decrease (P <
.01) in overall liver function testing, with a marked shift in
testing toward individual analytes.
Send-out testing decreased by 19% after implementation
<strong>of</strong> the new requisitions.
Discussion
For the purposes <strong>of</strong> evaluating and influencing laboratory
utilization, we found that considering test ordering data with
and without normalizing by patient load was useful. <strong>The</strong>
normalized data, or laboratory tests per patient visit, are best
for benchmarking specialties, provider groups, and the institution
within the industry. However, the overall ordering data,
without correcting for patient volumes, were useful for
targeting specialties for policy changes that would have the
most impact on laboratory utilization. For example, at our
medical center, although the transplant group was the highest
user <strong>of</strong> the laboratory per patient, laboratory policies targeting
internal medicine or the cancer center were more likely to
have a significant impact overall. In addition, focusing on the
nonnormalized high users was strategic for addressing operational
and client service issues in the laboratory.
<strong>The</strong> overall decrease in utilization may be the result <strong>of</strong>
heightened awareness <strong>of</strong> medical necessity requirements.
Medical necessity is emphasized in a number <strong>of</strong> ways,
including the requirement for diagnostic information, an
attestation by the ordering physician, and the use <strong>of</strong> ABNs.
<strong>The</strong> shift in ordering practice from panels to single analytes
is inferred to be a direct result <strong>of</strong> the test menu presentation.
Implementing the requisitions and, in particular, the
cascades increased clerical work for laboratory staff and
affected specimen processing and storage. However, fewer
write-in requests for laboratory tests and fewer send-out tests
partially <strong>of</strong>fset that effect.
Clinicians for the most part were accepting <strong>of</strong> the new
policies. Most <strong>of</strong> the initial complaints received by the laboratory
were related to features <strong>of</strong> the requisition that were
added for compliance purposes such as requisite diagnoses,
ABNs, and signatures. <strong>The</strong> features related to guidance in
test ordering were generally welcomed.
Conclusions
Ordering practices were affected markedly by requisition
design. Overall laboratory utilization as measured by
number <strong>of</strong> tests ordered per patient visit decreased significantly.
Patterns <strong>of</strong> test ordering shifted to increased number
<strong>of</strong> individual analytes and increased use <strong>of</strong> cascades, while
orders for panels declined.
From the Departments <strong>of</strong> 1 Pathology, University <strong>of</strong> California,
Irvine, and 2 Biostatistics, University <strong>of</strong> Washington, Seattle.
Address reprint requests to Dr Emerson: Chief <strong>of</strong> Clinical
Pathology, UCIMC Rt 38, 101 <strong>The</strong> City Dr S, Orange, CA 92868.
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884 Am J Clin Pathol 2001;116:879-884 © American Society <strong>of</strong> Clinical Pathologists