Teaching the microscopic examination of urinesediment to second year medical students using

the Urinalysis-Tutor computer programCarla Phillips,1 Paul J. Henderson,1 Lynn Mandel,2 Sara Kim,2 Doug Schaad,2

Mindy Cooper,3 Claudia Bien,1 Adam Orkand,1 Mark H. Wener,1

James S. Fine,1 and Michael L. Astion1*

The microscopic examination of urine sediment is acommon diagnostic tool taught to medical students,medical technologists, and others. The urine micro-scopic exam is difficult to teach because supervisedinstruction and textbook-based teaching suffer fromnumerous drawbacks. Here, we describe Urinalysis-Tutor, a computer program that uses digitized micro-scope images and computer-based teaching techniquesto systematically teach the urine microscopic exam. Inaddition, we report the results of a 2-year study thatevaluated the effectiveness of the program in 314 secondyear medical students who were required to use theprogram. The program contained two, 20-questionexams. In the first year of the study (1996), one ofthe exams was chosen as the pretest and the other as theposttest; the pretest had to be completed beforethe students viewed the contents of the program, andthe posttest was taken after finishing the tutorial. In1997, the order of the two exams was reversed. In 1996,159 students completed the study. The mean pretestscore was 34% (SD, 14%), the mean posttest score was71% (SD, 13%), and the improvement was significant(P <0.001, paired t-test). In 1997, 155 students partici-pated. The mean pretest score was 41% (SD, 11%), themean posttest score was 71% (SD, 13%), and the im-provement was significant (P <0.001, paired t-test). Thestudy shows that Urinalysis-Tutor helps medical stu-dents learn to interpret the microscopic appearance of

urine sediment and that it is feasible to implement thistutorial in a medical school class.

Routine analysis of urine is a part of the education ofmedical students, medical technologists, and other health-care workers because the analysis of urine chemicalconstituents, coupled with a careful review of the micro-scopic elements in urine sediment, can provide physicianswith valuable diagnostic information.

The most common approaches to teaching the exami-nation of urine sediment are supervised instruction at amicroscope and review of photomicrographs. These ap-proaches have serious drawbacks. Supervised instructionsuffers from variability in microscope quality and instruc-tor experience. In addition, many medical schools, medi-cal technology programs, and clinical laboratories do nothave the time, the staffing, or the equipment to provideproper supervised instruction. Lastly, specimens that ad-equately demonstrate the most important urine elementsmay not be available, and even when available, thesamples are often difficult to preserve for demonstration.

Although textbooks of photomicrographs (1, 2) candemonstrate rare specimens usually unavailable to in-structors, the quality of photos is variable and often doesnot faithfully represent what the student views throughthe microscope. It is also difficult to use photographs toaccurately demonstrate the various microscope tech-niques necessary to characterize specimens. These tech-niques include polarization, phase contrast, adjusting theplane of focus, simple manipulation of the light, and cellenumeration.

Over the last several years, faculty and staff in theUniversity of Washington Department of LaboratoryMedicine have been developing computer programs toteach image-based laboratory tests (for review, see (3)).The goal has been to use computer technology to over-come some of the drawbacks of traditional instruction.

Departments of 1 Laboratory Medicine and 2 Medical Education, Univer-sity of Washington, Seattle, WA 98195.

3 Division of Nephrology and Transplantation, Virginia Mason MedicalCenter, Seattle, WA 98111.

*Address correspondence to this author at: Department of LaboratoryMedicine, Box 357110, University of Washington, Seattle, WA 98195-7110. Fax206-548-6189; e-mail astion@mail.labmed.washington.edu.

Received March 23, 1998; revision accepted May 8, 1998.

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Our previous work includes PeripheralBlood-Tutor (4, 5)(Lippincott-Raven Publishers), which teaches the inter-pretation of peripheral blood smears; GramStain-Tutor(6–8) (Lippincott-Raven), which teaches the interpreta-tion of direct Gram stains of body fluids; Electrophoresis-Tutor (9) (Beckman Instruments), which teaches the inter-pretation of protein electrophoresis of serum, urine, andcerebrospinal fluid; Parasite-Tutor (10) (Lippincott-Raven), which teaches the microscopic identification ofclinically important parasites; and ANA-Tutor (11)(Sanofi Diagnostics Pasteur), which teaches the interpre-tation of the immunofluorescence assay for anti-nuclearantibodies, and others (12–14).

The focus of this article is Urinalysis-TutorTM (15)(published and distributed by Lippincott-Raven Publish-ers and also distributed by Bayer Diagnostics), a com-puter program that uses digital images, text, and micro-scope simulations to teach the microscopic examination ofurine sediment to medical students, medical doctors,medical technologists, and other healthcare workers. Wediscuss the contents of Urinalysis-Tutor, concentrating onuseful features of computer-based teaching, and we detailthe results of a 2-year study of .300 second year medicalstudents who were required to use the program in theircourse on the urinary system. The study suggests thatUrinalysis-Tutor is feasible to implement in the medicalschool curriculum and that it helps teach the interpreta-tion of the microscopic appearance of urine sediment.

Materials and Methodsprogram developmentUrinalysis-Tutor was written in Microsoft Visual Basic forWindows (Microsoft Corp.). The program runs underWindows on a computer with the following minimalhardware configuration: 80486 computer running at 33megahertz and equipped with 40 megabytes of hard diskstorage or a CD-ROM drive. The minimal display resolu-tion is 640 3 480, 256 colors.

The program was developed by a team of physicians,medical technologists, computer programmers, and art-ists. An early version of the program was tested bymedical technologists from the University of WashingtonMedical Center (Seattle, WA) and the Harborview Medi-cal Center (Seattle, WA). The feedback from this betatesting was used to prepare the final version of theprogram.

The program is based on images collected from freshurine sediments that were prepared in the clinical labora-tories at the University of Washington Medical Centerand the Harborview Medical Center. The images werecollected using a digital video microscope system, whichhas been described previously (5). Briefly, the hardwarecomponents of the system were as follows: a color CCDcamera (Javelin Chromachip II model #JE3462RGB, Jave-lin Electronics) mounted on a light microscope (Olympusmodel BH2, Olympus Inc.), an 80486 computer (Gateway2000 Inc.) containing a video imaging board (MVP-AT,

Matrox Electronic Systems Ltd), and a 13-inch closedcircuit television monitor (Sony) for image display. Theimaging board converted the analog camera signal into adigital image, which could then be saved and edited. Theimaging system was operated using Optimas image anal-ysis software (Optimas Corp.). Adobe Photoshop (AdobeSystems Inc.) was used to edit some of the digital images.Image enhancement could include color correction, noisereduction, and contrast and brightness adjustment; thegoal of image enhancement was to make the imagesappear nearly identical to images seen using a high-quality microscope.

medical student evaluationThe subjects in the study were medical students at theUniversity of Washington, who were required to useUrinalysis-Tutor in the second year, 34-h course on theurinary system (Human Biology 562). Directions for useof the program were given at the beginning of the 8-weekcourse. The students could use the program any timeduring the course by logging onto any of 15 networkedcomputers located in the University of WashingtonHealth Sciences Library.

The first class to use the program was 159 studentswho entered medical school in August 1994 and who usedthe program in March and April of 1996. The second classwas 155 students who entered in August 1995 and usedthe program in March and April of 1997.

The version of the program used for the study had twodistinct 20-question exams. In the first year of the study(1996), one of the exams was chosen as the pretest and theother as the posttest. The program required the studentsto take the pretest immediately after logging into theprogram and before they could view the contents of theprogram. The posttest was taken after completing Urinal-ysis-Tutor. In year 2 of the study (1997), the exam orderwas reversed to assess the equivalency of the pre- andposttests. Thus, the 1996 pretest was used as the 1997posttest, and the 1996 posttest became the 1997 pretest.Except for the reversal of the tests, the program used in1996 was the same as that used in 1997.

Student identification numbers and test scores wererecorded over the network in a Microsoft Access® data-base (Microsoft Corp.). SPSS for Windows, Ver. 7.0 (SPSSInc.) was used for statistical analysis. Student pretest andposttest data were compared with paired t-tests andanalysis of covariance (ANCOVA).

program descriptionUrinalysis-Tutor requires little or no experience withcomputers. It is driven completely by pointing with themouse and clicking the left mouse button. No supplemen-tary reading materials are necessary to use or to under-stand the contents of the program, and it takes 90–120min to complete the program.

A schematic of the contents of Urinalysis Tutor isshown in Fig. 1. The program is divided into the following

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sections: Introduction, Urine Sediment Structures, DiseaseAssociations, Image Atlas, and Final Exam.

The introduction uses two-dimensional illustrations,three-dimensional illustrations, photographs, and micro-scope images to teach renal anatomy, the formation ofurine, the basic steps in the laboratory examination ofurine, and an introduction to phase contrast microscopy,polarizing microscopy, and the use of stains. Details ofurine chemistry are not covered in Urinalysis-Tutor.

The section on urine sediment structures is the largestand most important part of the program. This section isdivided into subsections on cells, casts, crystals, andorganisms/artifacts. The cells that are detailed are whiteblood cells, red blood cells, epithelial cells, and oval fatbodies. A number of computer techniques help the stu-dent learn to identify and enumerate cells. For example, tolearn the enumeration of red and white cells, the studentsimulates moving the stage of the microscope to look atmultiple fields, and the program provides immediatefeedback regarding whether the student has correctlyidentified each cell in an image. Furthermore, in thediscussion of oval fat bodies, the student can change themicroscope from a bright field to a polarizing configura-tion to reveal the “Maltese cross” forms that identifycholesterol-containing oval fat bodies.

The tutorial covers the following casts: hyaline, gran-ular, waxy, fatty, renal cell, red cell, and white cell. Two-and three-dimensional illustrations as well as an anima-tion are used to illustrate how casts are formed, and threeto four images of each type of cast are shown withdescriptive text overlays. A variety of teaching techniquesenhance the discussion of casts. For example, the user canchange the plane of focus to help identify a hyaline cast. Inaddition, by pressing a highlight button, some casts thatcan be difficult to find, e.g., hyaline, granular, waxy, fatty,or renal casts, will be delimited by a red border (Fig. 2).The highlighting feature is also used to point out the

location of some of the visible red cells in a red cell castand some of the white cells in a white cell cast. Anothercomputer technique used to teach the identification ofcasts is the ability to change from bright field microscopyto either polarization or phase contrast microscopy. Thismimics the way a practicing medical technologist mightchange microscope configuration to help identify a cast. Achange in microscope configuration is available severaltimes, including identifying a fatty cast, using polariza-tion microscopy, and identifying a hyaline cast, usingphase contrast.

The section on crystals presents images of both normaland abnormal crystals. The normal crystals that are cov-ered are uric acid, hippuric acid, calcium oxalate, triplephosphate, calcium carbonate, calcium phosphate, andammonium biurate. The abnormal crystals are leucine,tyrosine (Fig. 3), cystine, bilirubin, cholesterol, sulfon-amide, and radiopaque dye. For each crystal, there aretwo to four distinct images with optional descriptive textoverlays and additional bulleted text describing pH andsolubility characteristics of the crystals and the diseasestates associated with each abnormal crystal. The crystalssection incorporates computer techniques such as theability to simulate polarization microscopy to distinguishuric acid crystals from cystine crystals and the ability tocompletely delimit the irregular shape of an ammoniumbiurate crystal.

The section on organisms and artifacts covers yeasts, aparasite (Trichomonas vaginalis), bacteria, sperm, fibers,and starch. An example of each is presented. A number ofcomputer teaching techniques are featured, includingthe ability to completely highlight all organisms and theability to invoke polarization microscopy to identify fibers.

The Disease Associations section defines glomerulone-phritis, nephrotic syndrome, pyelonephritis, and lowerurinary tract infections, and then allows the user toreview the characteristic microscopic findings associatedwith each condition. The image index is a reference toolthat allows access to 91 microscope images in the pro-gram. The images are listed under the following catego-ries: cells (15 images), casts (23 images), normal crystals(21 images), abnormal crystals (21 images), and organ-isms/artifacts (11 images). The images can be viewed oneor two at a time, and the text overlays can be added orremoved by clicking a button. The ability to directlycompare any two images in the index is a major advan-tage of the computer program over a textbook. This isillustrated in Fig. 4, which shows how a split screen can beused to help the student to differentiate uric acid crystalsfrom cystine crystals.

The two final exams each have 20 image-based ques-tions. The questions are in a variety of formats rangingfrom straightforward identification of urine sedimentstructures in a single image (Fig. 5) to the identification ofmultiple structures, using a microscope simulation tochange microscope configurations (e.g., phase contrast orpolarization microscopy), or to search the multiple fields

Fig. 1. Schematic of the Urinalysis-Tutor computer program.See Materials and Methods for details.

1694 Phillips et al.: Urinalysis-Tutor computer program

Fig. 2. Examples from the casts section of Urinalysis-Tutor.(A) A typical screen from the casts section of Urinalysis-Tutor showing an image of a waxy cast. Other images of casts (e.g., hyaline, granular, fatty, and others) canbe viewed by selecting the buttons on the top of the screen. More examples of waxy casts can be displayed by selecting the “Examples” button located at the lowerleft of the screen. (B) The image after the user selected the “Highlight” button located directly below the image. This button allows the user to outline the waxy castwith a red border.

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Fig. 3. Examples from the abnormal crystals section of Urinalysis-Tutor.(A) A typical screen from the abnormal crystals section of Urinalysis-Tutor showing an image of tyrosine crystals. Other images of abnormal crystals are viewed byselecting the buttons on the top of the screen. Two more examples of tyrosine crystals, including the one shown in (B), can be accessed by selecting the “Examples”button located at the lower left of the screen. These examples demonstrate variation in the appearance of the crystals.

1696 Phillips et al.: Urinalysis-Tutor computer program

in a slide for the structures. For each question, a detailedanswer is provided. Users are given their scores at the endof the exam.

ResultsThe results for the two medical student classes who usedUrinalysis-Tutor are shown in Table 1.

In 1996, 159 students completed the tutorial; in 1997,155 students completed the tutorial. In both years of thestudy, the improvement from pretest to posttest wassignificant (P ,0.001, paired t-test). Although the averagescore on the pretest in 1997 (41%; SD, 11%) was greaterthan the average score on the 1996 pretest (34%; SD, 14%)this difference was not significant.

The purpose of reversing the exams between 1996 and1997 was to control for the difficulty of the two exams.Ideally, the exams would be of equivalent difficulty, sothat a pre- to posttest improvement could not be solelybecause of a less difficult posttest. Because 1996 and 1997class performances were similar despite reversal of thetests, the pretest and posttest are approximately equiva-lent, and the improvement in test scores between pretestand posttest was because of learning the material and notbecause of a less difficult posttest.

DiscussionThe examination of urine sediment is one of many clinicallaboratory procedures that require the proper interpreta-tion of microscope images. Other common microscope-based diagnostic tests include peripheral blood smears,direct Gram stains, wet mounts of vaginal discharge, thedirect detection of parasites, the direct detection of fungi,and the anti-nuclear antibody test and related immuno-fluorescence assays for autoantibodies.

Physicians, such as family practitioners and generalinternists, commonly perform a subset of the microscope-based tests, most notably urine dipstick and microscopicexamination, the direct Gram stain, peripheral bloodsmears, and wet mounts (16). Therefore, it is not surpris-ing that directors of internal medicine residencies, physi-cians who teach internal medicine to medical students,and residents in training agree that it is important tomaster these laboratory procedures (17–19). Despite theperceived importance of this training, training of resi-dents and students is inadequate, as measured by surveysas well as by testing of physicians (17, 19). For example,Hilborne et al. (19) reported the poor performance ofresidents in performing urine microscopic exams andother image-based laboratory procedures. This has led

Fig. 4. The split-screen feature of the image index.The upper panel in the screen shows cystine crystals and uric acid crystals without polarization; the lower panel shows the same crystals under polarizing conditions.Only the uric acid crystals are birefringent.

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Fig. 5. An exam question from Urinalysis-Tutor, which tests the ability to recognize white blood cells, transitional epithelial cells, and squamousepithelial cells.The question is presented in (A) and the answer in (B). The user chose the answers correctly.

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many to conclude that more formal training is necessaryin medical school, in residencies, and as part of continuingmedical education for practicing physicians (17–19).

The most important reason that microscope-based lab-oratory tests are not adequately taught to medical doctorsis that the two most common teaching approaches, super-vised instruction at a microscope and textbook-basedteaching, have serious disadvantages. Supervised instruc-tion requires a great deal of resources, including speci-mens, microscopes, and an instructor’s time. Textbookshave variable image quality and cannot simulate themanipulation of the microscope. The difficulty of teachingmicroscope-based laboratory procedures in the medicalcurriculum has caused many medical schools to reducethe teaching of these tests.

To overcome the problems associated with teachingmicroscope-based laboratory tests, our faculty in theDepartment of Laboratory Medicine has developed Uri-nalysis-Tutor and related computer programs, includingGramStain-Tutor (6–8), PeripheralBlood-Tutor (4, 5), Par-asite-Tutor (10), and ANA-Tutor (11). In addition, wehave developed Microscopy-Tutor (20) (Lippincott-Raven), a program that complements the above programsby teaching the principles and practice of light micros-copy. Our educational software is currently in wide use atthe University of Washington in the medical school cur-riculum, the medical technology program, the pathologyand other residency programs, the nurse practitionercurriculum, and other undergraduate and graduate pro-grams. It is also in use in .3000 sites worldwide.

In this work, we studied the required use of theUrinalysis-Tutor in two consecutive classes (n 5 159 andn 5 155) of second year medical students. The improve-ment in scores between the exam taken before the tutorialand the exam taken after the tutorial shows that Urinal-ysis-Tutor helped students interpret the microscopic ex-amination of urine sediment. This result is similar toresults obtained in our previous studies of two of ourother programs, GramStain-Tutor, which was studied in.140 first year medical students over 2 years(8); andPeripheralBlood-Tutor, which was studied in .250 sec-ond year medical students over 2 years (5). All three

studies show that it is relatively easy to implement thetutorials in a medical school class using a library-basedcomputer network. All three of the programs continue tobe required in the preclinical medical school curriculum,and they are also being used optionally in the third yearclerkship in internal medicine.

Urinalysis-Tutor is used frequently in our clinical lab-oratory for training, continuing education, and as a refer-ence. Our laboratory also uses a related program that wedeveloped, Urinalysis-Review (21) (Lippincott-Raven),which provides additional exam questions. Currently,Urinalysis-Review is being distributed four times per yearto participating laboratories and schools, the goal being toallow supervisors and teachers to periodically monitorindividual and group performance regarding the abilityto interpret a urine microscopic exam. Urinalysis-Reviewcan be a stand-alone program, or it can integrate withUrinalysis-Tutor because the images from Urinalysis-Review are accessible from the Urinalysis-Tutor imageindex if the tutorial is run on the same computer.

Our future work will include a more detailed analysisof the Urinalysis-Tutor exam data (22). This study isdetermining the urine sediment structures that are mostdifficult for medical students to learn. The results will beused to modify Urinalysis-Tutor, and then the effective-ness of the revised tutorial will be studied in the next twoclasses of second year medical students. Thus, our currentsoftware development model, as illustrated by our workwith Urinalysis-Tutor, is to create a computer tutorial, tostudy its effectiveness, to establish that it is feasible to usein a large class, and then to use the results of the study asthe basis for improvements in the next version of thesoftware. We hope to apply this model to many of ourtutorials.

We thank the staffs of the clinical chemistry laboratories atthe University of Washington Medical Center and Har-borview Medical Center for participating in the evalua-tion of Urinalysis Tutor and providing quality specimens.In addition, we thank Chuck Rohrer for help with contentof the tutorial, Jennifer Lee and Nathan Kalat for pro-graming, Len Pagliaro for help with our digital videomicroscope, and Cathy Griffin for help regarding generalcomputing issues. Additional information about educa-tional software from the University of Washington De-partment of Laboratory Medicine can be found on thedepartment’s world wide web site at: http://www.labmed.washington.edu/Tutors/Tutor.Home.html, or atthe web site for Lippincott-Raven Publishers: http://www.lrpub.com/.

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Table 1. Performance of second year medical students onthe Urinalysis-Tutor pretest and posttest in 1996 (n 5 159

students) and 1997 (n 5 155 students).a

Year Test Mean, % SD, %

1996 Pretest 34 141996 Posttest 71b 131997 Pretest 41 111997 Posttest 71c 13

a 1996 pretest 5 1997 posttest; 1996 posttest 5 1997 pretest.b Significant increase compared with 1996 pretest score, paired t-test;

P ,0.001.c Significant increase compared with 1997 pretest score, paired t-test;

P ,0.001.

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