Serological Diagnosis of HumanImmunodeficiency Virus Infectionby Western Blot TestingThe Consortium for Retrovirus Serology Standardization

THE ACQUIRED immunodeficiencysyndrome (AIDS) epidemic and the in-creasing concern of both the public andgovernmental agencies about the test-ing of low-risk populations for AIDShave created an unprecedented demandfor serological testing for human immu-nodeficiency virus (HIV). Although theenzyme immunoassay for HIV antibod-ies was originally developed to screendonated blood, it is now routinely usedas a diagnostic tool in the workup forHIV infection. Unfortunately, the ex-

quisite sensitivity of the enzyme immu-noassay, coupled with less than 100%specificity, creates a potential for false-ly positive reactions. This featuremeans the test has a relatively poor pos-itive predictive value for populationswith a low prevalence of HIV infec-tions.1 Supplemental or confirmatorytests that are specific enough to distin-guish between the falsely positive re-sults of the screening test and the trulypositive ones must be used. Various lab-oratory assays offering greater specific-ity, including the Western blot test,2,3indirect immunofluorescence assay,3radioimmunoprecipitation assay,4 andothers using recombinant proteins as

antigens,5 have been adapted as alterna¬tive assays. Among these supplementaltests, the Western blot is the most infor¬mative and it is the current "gold stan¬dard" for confirmation of HIV serologi¬cal assays. The greatest disadvantageof the Western blot test is the lack of

r

standardization for reagents, test meth¬ods, and test-interpretation criteria.

In the context ofAIDS diagnosis or inthe testing of asymptomatic individualsfor HIV infection, a positive anti-HIVserology test has immense psychologi¬cal impact; therefore, it is crucial thatthe Western blot test be performed ac¬

curately using standardized methodsand reagents. In the absence of strongregional or national direction in this crit¬ical area of laboratory proficiency, theConsortium for Retrovirus SerologyStandardization was organized by rep¬resentatives from more than 30 blooddonor centers and public health, refer¬ence, clinical, and research laboratoriesthroughout the United States. Threetwo-day consensus development confer¬ences on the serological diagnosis ofHIV infection by Western blot testinghave been held (first conference, Bea-verton, Ore, Oct 5 through 7,1986; sec¬ond conference, Yountville, Calif, April8 through 10, 1987; and third confer¬ence, Scottsdale, Ariz, Dec 2 through 4,1987). Evaluation panels includingthree sets of 20 "problem" specimenseach, as well as data summaries fromparticipating laboratories, were used toevaluate the Western blot test as a con¬

firmatory assay and to develop recom¬mendations for Western blot test per¬formance. A preliminary report fromthe first two conferences was presentedin part on Oct 19, 1987, in testimonybefore the Subcommittee on Regulationand Business Opportunity of the HouseCommittee on Small Business by twomembers of the consortium, Patricia

Watson-Martin, MS, and James R.Carlson, PhD.6'7

The consortium's consensus groupconsidered scientific evidence and cur¬rent laboratory practice to develop an¬swers to the following questions:

1. How effective is the Western blottest as a serological assay for the diag¬nosis ofHIV infections?

2. What are the best criteria for West¬ern blot test performance, interpreta¬tion, and quality assurance?

3. What are the current needs and thefuture directions for serodiagnosis ofHIV infection?HOW EFFECTIVE IS THE WESTERNBLOT TEST AS A SEROLOGICALASSAY FOR THE DIAGNOSIS OFHIV INFECTIONS?

The Western blot test is currently themost sensitive and specific method inroutine use for the serological diagnosisof HIV infection. Test proficiency, how¬ever, is highly dependent on the use ofoptimum materials and methods and in¬terpretive criteria. A major advantageofthis test is that it defines the antibodyprofile to specific viral gene products(Figl).

The Western blot test should be usedonly in conjunction with other clinicaland laboratory findings, as recommend¬ed by the Public Health Service,8,9 toconfirm the clinical diagnosis of HIVinfection. For symptomatic individuals,clinical evidence of infection with a posi¬tive Western blot test provides criteriafor diagnosis. However, for asymptom¬atic individuals, other criteria including

Reprint requests to the Department of Pathology,School of Medicine, MS-1A, University of California,Davis, CA 95616 (James R. Carlson, PhD).

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Fig 1.—Illustration of human immunodeficiency virus components by Western blot analysis. Kd indicateskilodaltons.

history of high-risk behavior or resultsof other virological or serological stud¬ies may be necessary for the diagnosis ofHIV infection.

WHAT ARE THE BEST CRITERIAFOR WESTERN BLOT TESTPERFORMANCE, INTERPRETATION,AND QUALITY ASSURANCE?Performance Criteria

The Western blot test is a technicallydemanding laboratory procedure.Briefly, the test is performed by frac¬tionating purified HIV by molecularweight using electrophoresis on a poly-acrylamide gel. The separated HIV pro¬teins are transferred from the gel, viaelectrophoretic blotting, to a nitrocellu¬lose membrane and the blot is cut intostrips that are then reacted with testand control serum or plasma specimens.During incubation, ifanti-HIV antibod¬ies are present in the specimen, theywill bind to the viral antigens on thenitrocellulose strips. Visualization ofthe human anti-HIV immunoglobulinsspecifically bound to HIV proteins isaccomplished by enzymatic reaction of acolorless substrate, producing bands ofcolor on the nitrocellulose strip.

In three surveys conducted by theconsortium, considerable variation inmaterials and methods used for West¬ern blot testing was revealed. Table 1 isa summary of the reagents and proce¬dures used by laboratories participatingin the second and third conferences.These results probably reflect the widevariation and combination of methods

currently in general use. Standardiza¬tion ofmethods would require the evalu¬ation of many separate variables in mul¬tiple combinations. Our use of blindedevaluation panels has demonstratedthat there is more than one combinationof variables that will produce Westernblot tests of acceptable quality. For ex¬

ample, Fig 2 shows the reactivity of aserum sample from a patient with AIDStested with Western blots performed bythe 19 laboratories participating in thesecond conference. All laboratories re¬

ported a positive result for thisspecimen.

The members of the consortium haveworked together correlating data frommaterials and methods surveys and per¬formance on evaluation panels to devel¬op specific recommendations for West¬ern blot test performance. The technicalcomplexity and the diversity ofmethodsused by the members of the consortiumhave made this a difficult task. By com¬

paring the materials and methods usedfor the second and third conferences,some trends toward improved perfor¬mance can be demonstrated (Table 1).

The HIV antigen is the most criticalreagent in the Western blot assay. Con¬sortium members have placed an em¬

phasis on evaluating the quality of spe¬cific lots of commercially availableproducts10 and these results have re¬duced the number ofsources for antigenused by consortium members to thoseproducing the highest-quality reagents.As the quality of antigen has increased,the concentration of antigen on the blothas been reduced.

Table 1.—Summary of Two Western Blot TestMaterials and Methods Surveys*

Second ThirdMaterials Conference Conference

and Methods_(n = 19)t (n = 13)Antigen

SourceOrganon Teknika Corp 6f 4

Du Pont 4 5Genetic Systems Corp 1Hillcrest BiologicalsBio-Rad LaboratoriesProtatek Laboratoriesln-house

Epitope, IncNational Cancer

InstituteConcentration range,

(ig/mm 0.02-1.6 0.02-0.62Gel electrophoresls

Gel sizeFull-size gel 13 9

MinigelGel concentration

Continuous gelconcentration, %

8

10 15

12Gradient gel

concentration, %7-15

10-20

ImmunoassayBlocking

None

Milk

SerumGelatin

BSA*Reagent

unspecifiedSerum dilution

1:25

1:501:67

1:100 10

1:1000

ConjugateHorseradish

peroxidase 13Alkaline phosphataseBiotin/avidin

SubstrateDAB* 10

4CNÍNBT-BCIP* 1

•Survey data on transblot method (summary ofsecond and third conferences): time range for minigel,0.5 to 20 hours; current range for minigel, 200 to 1000mA; time range for full-size gel, 2.5 to 18 hours; andcurrent range for full-size gel, 25 to 700 mA.

fNo. of laboratories reporting; some laboratoriesused and reported on more than one method or reagentor failed to report.

ÍBSA indicates bovine serum albumin; DAB, 3,3'-diaminobenzidine; 4CN, 4 chloro-1-napthol; and NBT-BCIP, p-nitrotetrazolium blue-5-bromo-4-chloro-3-in-dolyl phosphate.

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Fig 2.—Western blot reaction of serum specimen from patient with acquired immunodeficiency syndrome tested by 19laboratories that participated in second consortium conference on Western blot test standardization.

Fig 3.—Human immunodeficiency virus Westernblot tests of serum from nonreactive donor (lane 1 );patients with acquired immunodeficiency syndrome(lanes 2 and 3); early seroconverter (lane 4); andhealthy donors with nonspecific human immunode¬ficiency virus reactivity (lanes 5 through 7).

Both full-size gels and minigels havebeen successfully used for electrophore-sis. Most laboratories have preferred a10% continuous gel.

The transblot method is also a criticalstep in the Western blot procedure; awide range of methods for electropho-retic transfer are used by laboratories.In general, the use of higher current fora shorter period of time yields the mostconsistent results. However, suchmethods require constant cooling andmay be more damaging to equipment.

Blocking of the unbound protein-binding sites on the blot to prevent non¬

specific binding of antibody is an impor¬tant step that is performed by themajority of laboratories. This can beaccomplished by preblocking or by theaddition of blocking agents to the bufferor wash solutions.

The majority of laboratories used a1:100 dilution for the sample, horserad¬ish peroxidase as the enzyme conjugate,and either 3,3'-diaminobenzidine or 4chloro-1-napthol as substrate. In gener¬al, all of the immunoreagents in Table 1have been shown to be easily optimizedto the Western blot by simple blocktitration.

A pure HIV-antigen preparation,combined with techniques that produceconsistent, clear Western blots capableof detecting antibodies to all of the ma¬

jor HIV proteins, is vital to proper in¬terpretation. Emphasis for standard¬ization should be placed on the overallperformance of blots with well-charac¬terized control specimens. It is impera¬tive that Western blots for HIV testinghave the minimum capacity to demon¬strate, in optimum high-titered controlserum samples, the antibody profile tothe following HIV proteins (p) and gly-coproteins (gp) (the numbers refer tothe apparent molecular weight in kilo-daltons) (Figs 1 and 3 [lane 2]): gpl60(precursor of env glycoprotein); gpl20(outer env glycoprotein); p66 (reversetranscriptase component of pol trans¬late); p55 (precursor of gag proteins);p51 (reverse transcriptase componentof pol translate); gp41 (transmembraneenv glycoprotein); p31 (endonucleasecomponent of pol translate); p24 (gagprotein); and pl7 {gag protein).Interpretive Criteria

Positive Interpretation.—The ma¬

jor HIV gene products of diagnostic im-

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Table 2.—Frequency of Virus-Specific Bands on Western Blot Test in Clinical GroupsNo. (%) of Western Blot Bands Present

Clinical No. With -*-Group (n)_Any Bands_p_17_p_24_p_3J_gp41_p_51_p55_p66_gp120/gp160

AIDS* (111)_110_38 (35) 66 (60) 81 (74) 107 (97) 90 (82) 40 (36) 96 (87)_103 (94)Symptomatict(165)_163_115 (71) 152 (93) 143 (88) 157 (96) 156 (96)_89 (55) 155 (95)_154 (94)High-risk^§(198)_168_127 (76) 151 (90) 149 (89) 161 (96) 161 (96) 106 (63) 161 (96)_163 (97)Low-risk§|| (1306) 200 146(73) 163(82) 164(82) 129(65) 129(65) 150(75) 123(62) 6/2611(23)

*AIDS indicates acquired immunodeficiency syndrome.tAt least one symptom of human immunodeficiency virus infection, but do not fulfill case definition of AIDS.6¿Includes homosexual men, hemophiliacs, intravenous drug users, and their sexual partners.^Includes enzyme immunoassay screening test results for both positive and negative samples.Includes specimens from blood donor centers

'Data for bands at gp120/gp160 were only available for 26 specimens.

portance by the Western blot test arep24, p31, gp41, and gpl20/gpl60. Table2 demonstrates that these bands are

consistently present in persons withAIDS, in those with clinical symptomsof HIV infection, and in subjects at highrisk for HIV infection. These bands arealso easy to discriminate visually on theblots, whereas bands at p51, p55, andp66 are more difficult to discern (Figs 1through 3). Table 2 also demonstratesthe characteristic loss of antibody re¬sponse to p24 (Fig 3 [lane 3]) and p31with disease progression, ie, symptom¬atic of HIV-infection vs AIDS clinicalgroups. In contrast, the presence ofantibodies to other envelope proteinsremains constant with diseaseprogression.

Four different "standard" criteria are

currently being used for a minimal posi¬tive Western blot test interpretation.These include those used for the onlyFood and Drug Administration-li¬censed Western blot test (du Pont)(presence of antibodies to p24, p31, andgp41 or gpl20/gpl60); the AmericanRed Cross criteria (presence ofantibod¬ies to at least one gene product fromeach of env, pol, and gag); the Associa¬tion of State and Territorial PublicHealth Laboratory Directors/Depart¬ment of Defense criteria (presence ofantibodies to any two of p24, gp41, andgpl20/gpl60); and the Consortium forRetrovirus Serology Standardizationcriteria (presence of antibodies to atleast p24 or p31 and gp41 or

gpl20/gpl60)(Table3).At a recent meeting, entitled "Con¬

sultation on Criteria and InterpretiveStandards of HIV Antibody Testing forClinical and Public Health Purposes,"sponsored by the Public Health Service(PHS) at the Centers for Disease Con¬trol, Atlanta, Feb 3 through 4, 1988,these various interpretive criteria werediscussed and summarized as shown inTable 4. The categories that were estab¬lished by the PHS consultation groupwere based primarily on current prac¬tice as summarized by experts in thefield and not on specific data used for thepurpose of establishing guidelines for

Table 3.—Consortium Consensus Criteria

Positive p24 or p31 and gp41 * orgp120/gp160*

Indeterminate Any bands present, but patterndoes not meet the criteria forpositive

Negative No bands present

•Glycoprotein bands should be typically diffuse.

HIV Western blot test interpretation.Our consortium has analyzed Westernblot testing data using both the PHSconsultation group's summary (Table 4)and our own consensus group recom¬mendations (Table 3), so that a practicalWestern blot testing interpretive stan¬dard can be established that is based onactual performance. These results areshown in Tables 5 and 6.

The PHS consultation group agreedthat category I (presence of antibodiesto p24, p31, and gp41 or gpl20/gpl60)was an unequivocal positive result. Thisdecision reflected the very conservativecurrent use ofthis interpretive criterionfor the Food and Drug Administration-licensed Western blot test as part of thetest protocol for reentry into the donorpool of those blood donors deferred ow¬

ing to a false-positive screening result.Our data support the use of category Ias a positive result; however, if thiswere the only criterion that was finallyestablished as an unequivocal positive,more than 50% of patients with AIDSwould be put into a "probable" positiveor indeterminate category. Our datasupport the inclusion of categories I,lia, and lib as unequivocal positive cri¬teria for Western blot testing. Applyingthese criteria to our data would increasethe percent positive for patients withAIDS to 79% without diminishing speci¬ficity. A positive result will usually bereflected in the presence of typicalbands at p24, p31, gp41, andgpl20/gpl60, but at a minimum bandsshould be present at p24 or p31 and gp41or gpl20/gpl60 (Table 3). The one speci¬men in PHS category lib from the low-

Table 4.—Summary of the Public Health ServiceConsultation Group's Interpretive Standards forHIV*-Antibody TestingPositive (I) p24, p31, and gp41 or

gp120/gp160Probably positive (II)

Ma p24 and gp41 orgp120/gp160

lib p31 and gp41 orgp120/gp160

lie gp41 and gp120/gp160lid Any other combination of

viral-specific bands, onefrom each gene product

Indeterminate (III)Ilia No more than one of p24,

p31, gp41, orgp120/gp160

Nib Other non-HIV-specificbands

Negative (IV) No bands present

*HIV indicates human immunodeficiency virus.

riskgroup that would be included in thisexpanded positive group was only atyp¬ical because it lacked reactivity to p24,similar to almost 20% of subjects with a

diagnosis ofAIDS. Human immunodefi¬ciency virus-specific bands that werepresent for this specimen included pl7,p31, gp41, p51, p66, and gp 120/gpl60.

Indeterminate Interpretation.—In¬determinate results represent the lim¬its of resolution for the Western blottest and should not be considered posi¬tive or negative. The correct evaluationof this result may be based on subse¬quent testing, including further serolo¬gical or virological determinations withthorough clinical and historical evalua¬tion. Persons yielding indeterminate re¬sults, eg, as shown in Fig 3 (lanes 4,5,6,and 7), may be retested by Western blotserological testing to monitor the devel¬opment of their immune response toother HIV proteins. Lack of further de¬velopment of antibody response byWestern blot testing in combinationwith negative clinical and historicalfindings for HIV infection is strong evi¬dence ofa nonspecific HIV Western blottest.

Category He is probably a positiveresult, since this pattern was only

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Table 5.—Public Health Service Consultation Groups Western Blot Test Interpretation Standards as Defined Within Clinical GroupsTotal No. (%) In Public Health Service Category*

Clinical No. -'- Group_Studied_|_Ma_lib_He_Md_Mia_¡Mb_IV

AIDSt_111_54 (49)_12 (11)_22 (20)_16 (14)_0J0)_6 (5)j_OJO)_1 (1)Symptomatic!_165_134 (81)_12 (7)_9J5)_5J3)_1 (1)||_2J1)_OJO)_2 (1)High-riskH#_198_141 (71)_15 (8)_10 (5)_2J1)_0J0)_1_J1)_0J0)_29 (15)Low-risk"! 1306 127 (10) 0 (0) 1 (0)tt 0 (0) 0 (0) 43 (3) 33 (3) 1102 (84)

*See Table 4 for explanation of categories. (Percentages may not add up to 100% because of rounding)tAIDS indicates acquired immunodeficiency syndrome.¿Bands present: gp41 and p55; gp41 and p66; p51, p66, gp120/gp160; gp41; gp41 and p55; and p31, p55, and p66.§At least one symptom of human Immunodeficiency virus infection, but do not fulfill case definition of AIDS.8Bands present: gp41 p55, and p66.

'Includes enzyme immunoassay screening test results for both positive and negative samples.#lncludes homosexual men, hemophiliacs, intravenous drug users, and their sexual partners"Includes specimens from blood donor centers.ttBands present: p31, gp41, and gp120/gp160.

shown in the AIDS, symptomatic, andhigh-risk groups; however, since ourconsensus group agrees that a positiveWestern blot test should be based on anantibody response to at least two differ¬ent gene products, this pattern of reac¬tivity should be included in the indeter¬minate category.

Category lid did not prove to be use¬

ful, since all but one specimen in our

study could be placed in one of the otherinterpretive categories. Specimenswith patterns of reactivity in this cate¬gory may be more difficult to interpretas positive, since by definition reactiv¬ity to the better-defined typical HIV-specific proteins, p24, p31, gp41, orgpl20/gpl60, can be absent. For thesereasons, category lid should be consid¬ered indeterminate.

Our data support the inclusion of thePHS consultation group's categoriesIlia and Illb as indeterminate results(Table 5). The groups with the highestproportion ofspecimens in these catego¬ries were at low risk for AIDS and prob¬ably represent nonspecific Western blottest reactivity.

Negative Interpretation.—Both ourconsortium and the PHS consultationgroup agree that a negative result is nobands present by Western blot testing(Fig 3 [lane 1]).Quality Assurance Criteria

The Western blot test should be per¬formed only in those laboratories withadequate proficiency. Testing should bedone on at least a weekly basis to main¬tain high levels of skill. Every testshould include at a minimum the follow¬ing controls: a strongly positive control(reactive to pl7, p24, p31, gp41, p51,p55, p66, and gpl20/gpl60); a weaklypositive control (reactive to p24 or p31and gp41 or gpl20/gpl60); and a nega¬tive control serum sample that is nonre-active. The laboratory should partici¬pate in a regular, rigorous externalproficiency-testing program. Because

Table 6.—Consortium for Retrovirus Serology Standardizations Western Blot Test Interpretation Standardsas Defined Within Clinical Groups*

TotalClinical No.Group_Studied Positive, No. (%) Indeterminate, No. (%) Negative, No. (%)

AIDSt_1V1_88 (79)_22 (20)_1 (1)Symptomatic*_165_155 (94)_8J5)_2 (1)High-risk§||_198_166 (84)_3J2)_29 (15)Low-risk§! 1306 128 (10) 76 (6) 1102 (84)

* Percentages may not add up to 100% because of roundingtAIDS indicates acquired immunodeficiency syndrome.}At least one symptom of human immunodeficiency virus infection, but do not fulfill case definition of AIDS.8¿Includes specimens with positive or negative results on enzyme immunoassay screening tests.includes homosexual men, hemophiliacs, intravenous drug users, and their sexual partners"Includes specimens from blood donor centers

of the subjective nature of interpreta¬tion, results should be reviewed inde¬pendently by at least two laboratorians,one of whom is at the supervisory ordirector level.WHAT ARE THE CURRENT NEEDSAND THE FUTURE DIRECTIONS FORSERODIAGNOSIS OFHIV INFECTION?

The most urgent need for Westernblot test standardization is the initiationof detailed studies designed to more

specifically define the most importantprocedural variables that will result inWestern blot tests with consistent highquality. To perform these studies, largevolumes of well-characterized controlserum samples must be obtained. Theuse of standard control specimens willhelp establish Western blot test perfor¬mance criteria.

During the past year, more reagentsand equipment for Western blottinghave become commercially available.Depending on their quality, availabil¬ity, and cost, these test componentsshould have a positive impact on West¬ern blot test performance standardiza¬tion. However, with the increase inavailability of Western blot reagents,more laboratories will begin testing,therefore making the need for standard¬ization and training even more urgent.

The external proficiency surveys thatare currently available are limited infrequency, degree of difficulty, andsample quality. The consortium recom¬mends the development of large serumpanels for proficiency testing on a fre¬quent and regular basis, in an attemptto define and limit interlaboratory vari¬ation. For example, the three serum-panel exchanges that were conductedby the consortium helped participatinglaboratories reduce variability in West¬ern blot test performance, with an over¬all improvement in the quality ofresults.

The Western blot test result is highlydependent on the technical skill and sub¬jective interpretation of the experi¬enced laboratorian. Many members ofthe consortium have gained this experi¬ence by tedious trial and error with verylittle guidance from national referencecenters. The establishment of a consen¬sus for Western blot test performancewill form a basis to establish educationalprograms in test performance and re¬sult interpretation for both laborator¬ians and physicians.

The establishment of even the mostrigorous criteria will not completelyeliminate the subjectivity and variabili¬ty inherent in Western blot testing. Weadvocate continued development andevaluation of new technologies that will

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increase the objectivity, specificity, andsensitivity of assays used for the serodi-agnosis of HIV infections.CONCLUSIONS

1. The Western blot test is currentlythe most sensitive and specific assay forHIV serodiagnosis that is in commonuse.

2. Western blot test proficiency ishighly dependent on the use of optimalreagents and procedures. The Westernblot test should have the minimum ca¬

pacity to demonstrate the antibody pro¬file ofpl7, p24, p31, gp41, p51, p55, p66,and gpl20/gpl60 using a strongly posi¬tive control serum sample.

3. The Western blot test should onlybe performed in those laboratories thatdemonstrate adequate proficiency byfrequent test runs, use of appropriatecontrols, and participation in a rigorousexternal proficiency-testing program.

4. The major gene products of diag¬nostic significance by Western blot test¬ing are p24 (gag), p31 (pol), and gp41and gpl20/gpl60 (env). A combinationof p24 or p31 and gp41 or gpl20/gpl60with or without other HIV-specificbands should be considered positive.

5. Indeterminate results should be re¬solved by further laboratory testing andclinical follow-up.

6. There is currently a great need forstandard control specimens and more

rigorous external proficiency-testingand training programs.

The consortium's consensus groupconcludes that the Western blot test is asensitive and specific method for HIVserodiagnosis, but this method is highlyReferences

dependent on the use of optimal re¬

agents and procedures and technicalskill. The greatest effort must now bemade to provide the needed standard¬ization for this critical serological assay.

Members of the Consortium for Retrovirus Se¬rology Standardization include the following:James R. Carlson, PhD, Chairperson, ConsensusDevelopment Group, Director of the AIDS VirusDiagnostic Laboratory for the California Univer-sitywide Task Force on AIDS, and Assistant Pro¬fessor, Departments of Pathology and InternalMedicine, School of Medicine, University of Cali¬fornia, Davis; Richard C. Alexander, MS, Super¬vising Public Health Microbiologist, Virology Lab¬oratory, Orange County Health Care Agency,Santa Ana, Calif; Rhoda L. Ashley, PhD, ResearchAssistant Professor, Department of LaboratoryMedicine, University of Washington, Seattle; De¬nis R. Burger, PhD, Scientific Director, Immuno¬logie Associates, Beaverton, Ore; Emily Carrow,PhD, Clinical Microbiology-Immunology Labora¬tories, University of North Carolina, Chapel Hill;Robert Chase, Lead Technician, TransfusionTransmitted Virus Laboratory, Mayo Clinic BloodBank, Rochester, Minn; Sherri Cyrus, MT(ASCP)SBB, Manager, Diagnostic Testing Services, BloodSystems Inc, Central Laboratory, Scottsdale,Ariz; Todd Damrow, PhD, Research Microbiolo-gist, Washington State Public Health Laborato¬ries, Seattle; Janice Diggs, Public Health Microbi¬ologist, Viral and Rickettsial Disease Laboratory,California State Department of Health Services,Berkeley; Joan Dragavon, MT(ASCP), ClinicalTechnician II, Department of Laboratory Medi¬cine, University of Washington, Seattle; DeborahErickson, Microbiologist, State Laboratory of Hy¬giene, Madison, Wis; Conchita Fernandez, PhD,StaffQA Immunologist, Miles, Inc, Cutter Biologi¬cal, Berkeley, Calif; Diane H. Field, Assistant Di¬rector, Technical Services, American Red Cross,Portland, Ore; Ron FitzGerald, Senior ResearchChemist, Bio-Rad Laboratories, Hercules, Calif;Ginger Floerchinger-Franks, MS, Public HealthMicrobiologist, Orange County Health Care Agen¬cy, Santa Ana, Calif; Cindy Handwerk-Leber, Re¬search Associate, Community Based Center ofGreater Kansas City (Mo); Jill Hannawell, Microbi¬ologist, State Laboratory of Hygiene, Madison,

Wis; Margaret Hanson, MT(ASCP) SBB, VirologyLaboratory Supervisor, Memorial Blood Center ofMinneapolis; Marjorie Hoffman, Public Health Mi-crobiologist, Viral and Rickettsial Disease Labora¬tory, California State Department of Health Ser¬vices, Berkeley; Michael Huntzinger,Microbiologist, Michigan Department of Health,Lansing; James E. Johnson, PhD, Chief, SpecialReference Laboratory, Veterans AdministrationHospital, Lexington, Ky; Howard I. Kim, PhD,Reference Laboratory, Newbury Park, Calif; Ste¬ven Kleinman, MD, Associate Medical Director,American Red Cross, Los Angeles; Jerry Kudlac,Director, Immunology and Metabolic DiseaseScreening, Oklahoma State Department of Health,Oklahoma City; Heidi Langan, Associated Patholo¬gist Laboratories, Las Vegas; Jean Leete, DrPH,Director, Abbott Reference Laboratory, AbbottPark, 111; Bonnie Lowry, MT(ASCP), ImmunologySupervisor, Smith-Kline Bioscience, Van Nuys,Calif; Craig Miller, PhD, Associate Scientist, OrthoDiagnostic Systems, Inc, Raritan, NJ; Richard C.Moody, Serology Division Supervisor, AlabamaDepartment of Public Health, Montgomery; JeffMorgan, MT(ASCP), Supervisor, Clinical Refer¬ence Laboratory, Genetic Systems Corp, Seattle;Gary L. Norman, PhD, Assistant Professor of Clin¬ical Pathology, Laboratory for Viral Oncology andAIDS Research, University of Southern Califor¬nia, Los Angeles; Howard F. Taswell, MD, MedicalDirector, Mayo Clinic Blood Bank and TransfusionServices, Rochester, Minn; Roger N. Taylor, PhD,Microbiologist, Centers for Disease Control, Atlan¬ta; W. Michael Tregellas, MS, MT(ASCP), Direc¬tor, Medical Technical Operations, Blood SystemsInc, Central Laboratory, Scottsdale, Ariz; VictorC. W. Tsang, PhD, Centers for Disease Control,Atlanta; Patricia Watson-Martin, MS, TechnicalCoordinator, Immunologie Associates, Beaverton,Ore; Judith C. Wilber, PhD, Virologist, San Fran¬cisco Department of Public Health; Janice M. Wil¬liamson, BB(ASCP), Center for Blood Research,Boston; JoAnn Yee, MT(ASCP), Serology Supervi¬sor, AIDS Virus Diagnostic Laboratory, Universi¬ty of California, Davis.

The three consortium conferences were spon¬sored by Immunological Associates, Inc, Beaver¬ton, Ore (first conference), the California Univer-sitywide Task Force on AIDS (second conference),and Blood Systems Inc, Scottsdale, Ariz (thirdconference).

1. Reesnik HW, Huisman JG, Gonsalves M, et al:Evaluation of six enzyme immunoassays for anti-body against human immunodeficiency virus. Lan-cet 1986;2:483-486.2. Tsang VCW, Peralta JM, Simons AR: Enzyme\x=req-\linked immunoelectrotransfer blot techniques(EITB) for studying the specificities of antigensand antibodies separated by gel electrophoresis.Methods Enzymol 1983;92:377-391.3. Carlson JR, Yee J, Hinrichs SH, et al: Compari-son of indirect immunofluorescence and Westernblot for detection of anti\p=m-\humanimmunodeficiency

virus antibodies. JClin Microbiol 1987;25:494-497.4. Kitchen LW, Barin F, Sullivan JL, et al: Aetiol-ogy of AIDS-antibodies to human T-cell leukemiavirus (type III) in hemophiliacs. Nature 1984;312:367-369.5. Thorn RM, Beltz GA, Hung CH, et al: Enzymeimmunoassay using a novel recombinant polypep-tide to detect human immunodeficiency virus env

antibody. J Clin Microbiol 1987;25:1207-1212.6. Barnes DM: New questions about AIDS testaccuracy. Science 1987;238:884-885.7. Accuracy of HIV testing raises concerns, Micro-

scope on Washington. Lab Med 1988;19:11-12.8. Classification system for human T-lymphotro-phic virus type III/lymphadenopathy-associatedvirus infections. MMWR 1986;35:334-339.9. Classification system for human T-lymphotro-phic virus (HIV) infection in children under 13years of age. MMWR 1987;36:225-236.10. Carrow EW, Midgett JS, Bowdre JH, et al:Variability of Western blot patterns from sera ofhemophiliacs determined with different human im-munodeficiency virus antigen. Serodiagnosis Im-munotherapy 1987;1:413-422.

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