clin serological microbiology laboratory · 35clin pathol 1995;48:358-363 serological testing in a...

35 Clin Pathol 1995;48:358-363

Serological testing in a microbiology laboratoryof specimens from patients with suspectedinfectious disease

D J Waghorn

AbstractAims-To determine how the micro-biology laboratories of one region pro-cess serological requests from patientswith suspected infectious illness, referredto as "clinical syndrome" type patients inthis study; to consider areas where im-provement in the associated serology ser-vice could be made.Methods-A prospective two month col-lection of data on all serological requestsfrom patients with suspected infectious ill-ness was undertaken. A questionnaire onlaboratory policieslprocedures was alsocompleted by the 10 departments takingpart.Results-Serology specimens from "clin-ical syndrome" patients accounted for1-2% oftotal microbiology samples. Therewas significant variation in some of thepolicies/procedures carried out by the 10laboratories when handling serological re-quests. Differences were seen in the use oflaboratory protocols for test processing,range oftests performed, demand for sec-ond (convalescent) serum samples, stor-age of serum samples, and reporting ofresults.Conclusions-The laboratory man-agement of "clinical syndrome" type re-quests is complex. Individual pathologydepartments vary in the way they handleserology specimens but this study high-lighted areas which may contribute to im-proving the appropriateness oftesting andthe more efficient use of serology re-sources. These include improving (1) clin-ician education, (2) pathology requestforms to encourage better clinical in-formation, (3) appropriate laboratory pro-tocols to ald decision making on testselection, (4) percentage of convalescentserum samples received together withlonger serum sample storage, and (5)turnround times of serology reports.(7 Clin Pathol 1995;48:358-363)

Keywords: Serological testing, infectious diseases, mi-crobiology laboratory.

Over the past decade, there has been an in-creasing awareness and analysis of the ap-propriateness of laboratory tests. This has beenstimulated by concern over both increasingcosts of testing and a desire to improve the

overall use of pathology services.' To date,such studies have mainly been carried out byhaematology2 or biochemistry' departmentswhere requests and tests are more easily definedand where increasing automation of laboratorymethods permits easier systematic analysis ofthe tests performed. In microbiology labora-tories a review of requests received and sub-sequent tests performed is more complex.Compared with haematology and biochemistrydepartments, there is often a greater need tointerpret the clinical information given beforedeciding on which laboratory tests to perform.Results of primary testing may also stimulatethe need for secondary tests. In no area isthis more important than with blood samplesreceived for serological examination.

All clinical microbiology laboratories acrossthe United Kingdom will receive serum samplesfrom patients who have presented to clinicianswith a "clinical syndrome" suggestive of a pos-sible underlying infectious disease, where thediagnosis requires serological investigations.The types of disease falling into this descriptioncan be relatively well-defined-for example,atypical pneumonia, or can be broad andvague-for example, post-viral illness. How-ever, these types of clinical problem often needserological testing against a range of micro-organisms including virological (Epstein-Barr,influenzae, coxsackie), bacteriological (Le-gionella, Mycoplasma) and parasitological (Toxo-plasma) pathogens. When samples are receivedfrom such patients it may be difficult to decideon the most appropriate tests to perform. Theinformation given on the request form is criticalto the decision making process and the qualityofthat information is often poor. Even the basiccompletion of a patient's name, date of birthand sex can influence subsequent processing.After patient identification has been con-sidered, clinical details are critical and for vir-tually all serological tests, knowledge of thedate of onset of illness is vital.The decision on which tests to perform on

"clinical syndrome" requests often falls to themicrobiology laboratory and although this typeof request comprises only a small percentageof overall specimen numbers, it may generatea significant amount ofwork for both laboratoryand medical staff within the departnent. In anattempt to analyse how microbiology de-partments process such serological requests andto look for potential ways of improving theservice, a study was undertaken in 10 districtlaboratories of the Oxford region.

Department ofMicrobiology,Wycombe GeneralHospital,Queen AlexandraRoad,High WycombeHP11 2TTD J Waghorn

Correspondence to:Dr D J Waghom.Accepted for publication19 July 1994

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Serological testing of specimens from patients with suspected infectious diseases

Questionnaire on serological testing of infectious "clinical syndrome" requestsTotal number of specimens processed in microbiology annuallyTotal number of specimens processed in virology/serology during 2 month period of studyTotal number of "clinical syndrome" requests processed during 2 month period of studyWhat happens to "clinical syndrome" requests after arrival in the laboratory?How are decisions made on which tests to perform?a) Are there laboratory protocols for specific "clinical syndromes" described?b) Are requests reviewed by MLSO staff and tests decided by them?c) Are requests reviewed by medical staff and tests decided by them?d) Are requests reviewed mainly by MLSO staff with review by medical staff on someoccasions?If answer d), under what circumstances are requests reviewed by medical staff?Under what circumstances are second (convalescent) serum samples requested?When a second serum is needed, how is the request made ie by telephone or written report?When a second serum is requested, are further clinical details including date of onset ofillnessa) automatically asked for?b) only asked for if not adequate with first request?c) not asked for?When a second serum is requested, is a time interval between serum samples suggested tothe clinician?Does the time interval advised vary for different "clinical syndromes"?If yes, give detailsIf a second serum is requested but not receiveda) what action is taken by the laboratory?b) would tests be performed on the first serum sample onlyIf yes, under what circumstances?How long are serum samples from "clinical syndrome" requests kept?In "clinical syndrome" investigations, results are often obtained at varying times according tobatch testing, referral to other laboratories etc. Are results reporteda) as each individual test is completed?b) as batches of tests are completed?c) when all tests are completed including reference laboratory results?Are comments added to reports to help the clinician with interpretationa) always?b) sometimes?c) never?If only sometimes, under what circumstances would comments be added?The following are examples of the most common "clinical syndrome" type requests. Namethe tests that would be considered part of routine serological investigations for eachsyndrome describeda) 50 year old male, with ? atypical pneumonia.b) 20 year old female, with persistent general malaise following viral illness.c) 35 year old male, with fever and cervical lymphadenopathy.d) 40 year old female, with general malaise, abnormal liver function tests, ? hepatitis.e) 30 year old female, with 'flu-like illness and arthralgia.f) 50 year old male, with ? pericarditis.

MethodsThe Oxford region contains 10 microbiologydepartments all of which receive specimensfrom their local inpatients and outpatients de-partments and from general practitioners. Onedistrict has separate bacteriology and virol-ogy/serology departments so that for the pur-poses of this study, only the virology/serologysection contributed. This same district acts asa referral serology unit for most ofthe other ninedepartments. One other laboratory associatedwith Royal Air Force services receives a sig-nificant number of serology specimens frommilitary sources both home and abroad.The study was conducted in two parts.

Firstly, a questionnaire was distributed to eachlaboratory for comparison of the proceduresused for processing "clinical syndrome" re-

quests (table 1). A "clinical syndrome" requestwas defined as a request for serological in-vestigations on a patient whose details only givea general description of a suspected underlyinginfectious illness. The illness could be acuteand specific such as atypical pneumonia, orchronic with only vague signs and symptomsdescribed-for example, general malaise fol-lowing influenza-like illness.The second part of the study consisted of

a prospective collection of data on "clinicalsyndrome" requests received by the 10 de-partments over the two month period, June/July1993. A table was designed and distributedto all laboratories for data collection. Each

laboratory was asked to record the followinginformation:

1 Does the request form contain adequatepatient details by giving the full name, ageand sex?

2 State the clinical details and/or suspecteddiagnosis given by the clinician.

3 Does the request give enough clinical in-formation to allow an immediate decisionon appropriate tests to be performed?

4 Is the date of onset of illness given?5 Has the clinician requested specific tests

he/she wishes the laboratory to perform?6 Has the clinician left the decision to the

laboratory by requesting "viral titres" or

equivalent?7 Do the laboratory staff (either technical or

medical) consider it necessary to directlycontact the requesting clinician to gainmore details about the case?

8 Is a second (convalescent) serum con-

sidered necessary?9 Has a second specimen been received and

if so the date taken?10 Is further clinical information given with

the second serum?11 How many tests are performed at the prim-

ary laboratory?12 How many tests are performed at reference

laboratories?13 Record the time interval between arrival of

the first request and the report of the final

Table 1

Q.1Q.2Q.3Q.4

Q.5Q.6Q.7

Q.8

Q.9

Q.10

Q.1lQ.12

Q.13

Q.14

YES/NOYES/NOYES/NO

YES/NO

YES/NOYES/NOYES/NO

YES/NOYES/NO

YES/NO

YES/NOYES/NOYES/NO

YES/NOYES/NOYES/NO

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Table 2 Compilation of data from answers to questions I to 3 in questionnaire

Laboratory

1 2 3 4 5 6 7 8 9 10

Total number of specimens processed in microbiology dept. -t 113000 158000 131 000 165000 37000 92000 24000 110000 116000annuallyTotal number of specimens processed in virology/serology 50000 17000 31 000 18500 11100 5000 22800 8200 22000 18000section of dept. annually*Total number of "clinical syndrome" requests annually* 2 900 1 300 4 000 1 600 1 300 400 800 1 300 1 100 1 700% "Clinical syndrome" requests of virology/serology total 6 8 13 9 12 8 4 16 5 9% "Clinical syndrome" requests of microbiology total -t 1 2 5 1 1 1 1 5 1 1-5

* Total numbers extrapolated from figures collected over the two month study period.t Laboratory 1 has separate bacteriology department not involved in this study.

results (including those from referencelaboratories) sent to the clinician.

14 With the investigations performed, has asignificant positive result been found?

A list of specimens and requests commonlyreceived by virology/serology laboratories, butto be excluded from the study, was also dis-tributed. This comprised the following: allswabs/aspirates for viral culture/antigen testing;other miscellaneous material (for example, cer-ebrospinal fluid, faeces) sent for viral culture/antigen testing; all antenatal serology; all hep-atitis B vaccination associated serology; all hep-atitis B antigen screening-for example, pre-dialysis, preoperation; all specific HIV andsyphilis serology requests originating from Gen-ito-urinary clinics, insurance requirements,etc.; all "immunological" type requests-forexample, complement levels, C-reactive pro-tein; and all chlamydial culture/antigen tests.

All data was returned to the author onemonth after the period of study to allow forthe arrival of convalescent serum samples fromrequests received in July.

ResultsThe results from the questionnaire arm of thestudy were as follows:

Questions 1-3-"Clinical syndrome" re-quests comprise 8-10% of virology/serologyspecimens annually and 1-2% of total mi-crobiology samples across the Oxford region(table 2). Laboratory 8 had a higher percentageof "clinical syndrome" specimens because ofrequests originating from military sources.

Question 4-Six departments use protocolsto guide MLSO staff on which tests to perform.One laboratory uses MLSO review of eachindividual request with medical referral if ne-cessary, whilst in three laboratories review ofrequests is carried out solely by medical staff.Reasons given for medical review in the pro-tocol directed units include inadequate in-formation not conforming to a protocol, nodate of onset given, or request considered tobe of specific medical interest.

Question 5-Second or convalescent serumsamples are requested according to (1) the dateof onset given, (2) the type of illness orclinical details described, (3) the type of testavailable-for example, paired serum sampleswould always be required if complement fix-ation tests (CFTs) were the method of test, (4)the protocol directive.

Question 6-Five departments only send awritten (computer) report asking for a secondserum sample, whilst the other 50% also tele-phone the clinician directly depending on thecase.

Question 7-Only two laboratories auto-matically ask for further clinical details to ac-company a second serum whilst three othersrequest them if inadequate details were sup-plied with the first sample. Five laboratoriesmake no mention of the importance of furtherinformation such as the date of onset of illness.

Questions 8 and 9-All 10 departments sug-gest time intervals between serum samples.However, three give no variation in time in-terval for different "clinical syndromes", fourunits vary their advice for some suspected in-fections such as Borrelia or Legionella, whilstthree laboratories state a time interval ac-cording to the individual case. Around 10 daysis the most common time gap suggested.

Question 10-If a second serum fails to ar-rive, six laboratories take no further actionwhereas four units send a report after three tofour weeks reminding the clinician that a sec-ond sample is still awaited. Only two de-partments would not perform any serology onan acute serum sample alone. Seven unitswould carry out tests if the clinical detailssuggested an infection for which a single titrecould still be diagnostic. This would par-ticularly depend on the date of onset, if known,and the type of test. One laboratory tests allserum samples even if convalescent specimensfail to appear.

Question 11-Serum samples are stored forwidely varying periods of time. One laboratoryonly keeps aliquots for one month, four labora-tories store for up to four months, three unitskeep serum samples for 12 months, and twodepartments manage to store for several years.

Question 12-There are significant differ-ences in result reporting. One laboratory waitsfor all tests to be completed before sending areport whilst three departments release testresults as they are individually completed. Sixunits send reports as batches of tests are fin-ished.

Question 13-Three departments alwaysadd interpretative comments to reports whilstthe other seven units add comments in specificcases only. Examples quoted where commentsmay be added include all CFT results, singleserum results, when reporting IgM and IgGlevels, or "if requester is unlikely to understandthe result".

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Table 3 Examples of "clinical syndromes" and range of infections tested by 10 laboratories (Q. 14 in questionnaire).Figures in parentheses represent number of laboratories performing tests

(a) 50 year old man, ? atypical pneumonia

(b) 20 year old woman, persistent malaisefollowing viral illness

(c) 35 year old man, fever and cervicallymphadenopathy

(d) 40 year old woman, general malaise,abnormal liver function tests, ? hepatitis

(e) 30 year old woman, 'flu-like illness andarthralgia

(f) 50 year old man, ? pericarditis

Question 14-See table 3. In example (a)there is a broad agreement over the rangeof tests considered appropriate. Example (b)provides a wider spectrum of investigationsbut one laboratory argues that there are no

appropriate tests for this kind of clinical picture.General consensus is reached for example (c)with the same three tests performed by eightlaboratories. In example (d) investigations foracute hepatitis A or B are unanimous, but someother potential pathogens are sought if tests forhepatitis A and B prove negative. The widestrange of responses is given to example (e) with19 different infections investigated. The onlypathogen appearing on all laboratory lists isrubella. With example (f), the same five po-

tential pathogens are investigated by seven de-partments.A summary of the prospective data collected

by the 10 departments for the second part ofthe study is given in table 4. One laboratorywas unable to provide the majority of datarequested because of staffing difficulties duringthe study period.

Mycoplasma (10), LegioneUla (10), Q fever (10), Chlamydia (9), InfluenzaeA+B (9), Adenovirus (7), Respiratory syncytial virus (5), Cytomegalovirus(2), Enterovirus (1)Epstein-Barr virus (8), Cytomegalovirus (6), Toxoplasma (6), Enterovirus (6),Mycoplasma (4), Influenzae A+B (4), Adenovirus (3), Chlamydia (2),Q fever (2), Respiratory syncytial virus (1), Mumps (1), None (1)Epstein-Barr virus (10), Toxoplasma (10), Cytomegalovirus (8), Anti-streptolysin 0 titre (2), Mumps (2), Mycoplasma (1), Chlamydia (1),Influenzae A+B (1), Adenovirus (1), Enterovirus (1), Rubella (1), Herpessimplex virus (1), HIV (1), Respiratory syncytial virus (1)Hepatitis B virus (10), Hepatitis A virus (10), Cytomegalovirus (8),Epstein-Barr virus (7), Hepatitis C virus (2), Leptospira (2), Toxoplasma (1),Mycoplasma (1), Legionella (1), Q fever (1)Rubella (10), Parvovirus (9), Mycoplasma (8), Influenzae A+B (7),Chlamydia (5), Adenovirus (4), Enterovirus (4), Hepatitis B virus (4),Q fever (4), Epstein-Barr virus (3), Anti-streptolysin 0 titre (3), Borrelia (3),Mumps (2), Respiratory syncytial virus (2), Yersinia (2), Legionella (1),Toxoplasma (1), Syphilis (1), Cytomegalovirus (1)Enterovirus (10), Mycoplasma (7), Influenzae A+B (7), Q fever (7),Chlamydia (7), Adenovirus (5), Epstein-Barr virus (2), Cytomegalovirus (2),Legionella (1), Mumps (1), Anti-streptolysin 0 titre (1), Respiratory syncytialvirus (1)

Most laboratories received requests with ad-equate patient details in over 90% of cases butin two units, up to 15% of forms lacked fullpatient information. There was a wider vari-ation in the assessment of whether requestsprovided adequate clinical details (range 60-96%). Three units with a lower percentage ofadequate clinical information were also notusing protocols. Only three laboratories re-

ceived dates of onset of illness on more than40% of requests. Each department was askedto provide a copy of the serology form used bytheir clinicians and in three laboratories withpoor date of onset information, the card lackeda specific request box for this data. By contrast,the three laboratories with a response of over

40% specifically ask for a date of onset on theirserology forms.

Across the region, clinicians demanded spe-cific tests in approximately 50% of "clinicalsyndrome" cases. A general request for "viraltitres" or some similar description was givenon 50% of forms. Departments varied widelyin their use of direct clinician contact. Half of

Table 4 Summarised data of "clinical syndrome" requests received from 10 departments over the two month period

Laboratory

1 2 3 4 5 6 7 8 9 10

1 % Requests giving adequate patient 90 92 92 85 94 87 100 99 89 94details

2 % Requests giving adequate clinical 86 80 95 88 NA 60 66 96 67 81details to decide on which tests

3 % Requests giving date of onset of 43 46 30 28 NA 30 29 11 44 20illness

4 % Requests asking for specific tests 55 52 45 65 74 45 60 35 24 725 % Requests asking for "viral titres" or 55 49 55 42 30 69 44 71 81 31

equivalent6 % Requests needing direct clinician 2 14 1 13 NA 4 29 1 51 2

contact7 % Requests needing second serum 33 59 15 41 NA 22 63 33 79 378 % Second serum samples received NA 53 35 20 NA 33 29 39 44 299 % Second samples giving further NA 35 0 29 NA 20 17 4 30 19

clinical details10 % Tests performed at primary 95 48 85 47 NA 3 46 97 50 49

laboratory11 % Tests performed at reference 5 52 15 53 NA 97 54 3 50 51

laboratory(s)12 Average time (days) between first 8 7 8 5 NA 8 6 7 NA 4

serum and final report:(a) if tests performed at primary

laboratory only;(b) if tests also performed at NA 22 21 21 NA 15 19 19 21 19

reference laboratory(s)13 % Requests producing a significant 7 19 14 8 8 7 18 17 10 10

positive result

NA= data not available.

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Waghorn

the laboratories rarely contacted a clinician(<5% ofrequests) whereas in two units, doctorswere consulted regarding approximately 30%and 50% ofspecimens. Investigations requiringsecond serum samples varied from 15 to 79%(average 42%) but when a convalescent samplehad been asked for, only one laboratory ob-tained a 50% response (average 35%). Therewas also a failure to obtain further clinicaldetails with the second serum sample in 65-100% of cases. Laboratories 1 and 3 performmost serological investigations in-house as theyare also Public Health Laboratories. Labor-atory 6 is a small unit sending nearly all serologyto laboratory 1. Laboratory 8, although small, isa more self-sufficient unit as it handles militarysource specimens. The other six departmentsare similar in terms ofrepresenting large districtlaboratories which require the help of sec-ondary reference units for some serologicaltests. The ratio of tests performed within theprimary laboratory and those sent to referencelaboratories was remarkably consistent at aratio of 1: 1 across these six districts.From the data collected by most units, it

was possible to calculate the average time takento complete investigations on a "clinical syn-drome" request for both in-house and referenceserology. An average of 6-5 days was taken tocomplete in-house investigations whilst workrequiring reference testing took an average of20-2 days. The number of "clinical syndrome"requests producing a significant positive resultvaried across the region with some laboratoriesachieving over double the rate of others(average 12%).

DiscussionOver recent years there have been several stud-ies of the use of hospital clinical laboratories45and in particular the appropriateness of testscarried out and the efficiency ofresources avail-able. Serology is not a discipline that has re-ceived much attention but most clinicalmicrobiologists throughout the United King-dom will be only too aware of the intrinsicproblems that their serological workload pres-ents. The most difficult aspect is the processingof requests from patients with "clinical syn-dromes" suggestive of possible infectious dis-ease.

Clinicians vary greatly in their test orderingbehaviour. One publication listed 32 differentreasons for ordering a test including "frus-tration at nothing else to do".6 When cliniciansface patients complaining of vague symptomssuch as general malaise or myalgia/arthralgia,there is an almost automatic tendency for aserum sample to be taken for "viral titres".This study is the first to attempt to show howclinical laboratories in one region manage suchrequests.As expected, "clinical syndrome" requests

contributed a fraction to the total of mi-crobiology specimens and even within the ser-ology section itself, these samples formed asmall minority of overall numbers. For "clinicalsyndrome" requests basic patient details may

influence which tests are performed. A returnfrom two laboratories of less than 90% ad-equately completed patient details was un-satisfactory. The use of laboratory protocols forserology tests has advantages and dis-advantages. Their application can lessen theneed for more detailed clinical information andcan improve the efficiency of the laboratorybut they may encourage increased unnecessarytesting because they are by definition designedfor an average patient.7 Protocols or guidelinesare more likely to succeed if they are agreedjointly by laboratory staff and clinicians, withregular review, but achieving consensus on thecriteria for whether a test is appropriate for aparticular clinical setting is problematic. Pro-gress, however, can be achieved and in theauthor's own district, following discussionswith relevant clinical colleagues, laboratoryguidelines have been drawn up for the mostappropriate tests to be performed on patientswith a history of influenza-like illness followedby arthralgia, one ofthe most common "clinicalsyndrome" type requests. Clinician educationin the use of the laboratory, in the form oflectures, seminars or guidelines, has been pro-posed as the most promising long term ap-proach to influencing test ordering behaviour.8Many clinicians are unaware of how best toinvestigate, which tests to order and how muchclinical information to give the laboratoryespecially on "clinical syndrome" type patients.The finding that 50% of forms asked for "viraltitres" demonstrates clinicians' ignorance andhighlights the responsibility given to labor-atories as the clinician has, in effect, passed overdecision making on appropriate investigationsto the laboratory.

In this study two units declared that ser-ological testing would not be performed solelyon acute serum samples; such a policy mustundoubtedly result in missed diagnoses. In an-other department, investigations are carried outon every sample which must lead to a numberof inappropriate tests with the added concernthat single titre results could mislead the clin-ician. A review of both these extremes of prac-tice was advised in the departments concerned.Storage space is the obvious limiting factor fordetermining how long laboratories are able tokeep serum samples. However, the occasionalneed to re-examine serum samples is so im-portant that all laboratories should be en-couraged to store serum samples for aminimum of six months and preferably oneyear. The percentage of requests quoting a dateof onset of illness was disappointingly low inthis study. Knowledge of the date of onset ofa suspected infectious illness is often criticalnot only for making decisions on which teststo perform but also on the interpretation ofsubsequent results. A simple amendment tothe request form, specifically asking for a dateof onset should improve this response.Acute serum samples from some "clinical

syndrome" type patients will inevitably becomeredundant as subsequent clinical events orother investigations reveal a diagnosis, but test-ing ofpaired serum samples in parallel is almostobligatory for the diagnosis of some infections.

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In this study 50% oflaboratories took no actionif second serum samples failed to arrive. Thisindoubtedly contributed to the poor responseseen to second serum sample requests (average35%). Additional clinical details rarely ac-companied the second serum sample but onlyhalf of the laboratories specifically asked clin-icians for further information. As a con-sequence, departments were urged to reviewtheir procedures both in the way they requestsecond serum samples and the action takenwhen convalescent samples fail to arrive. Asecond serum sample response rate of 50%,achieved by one unit, should be an attainablegoal, and the development ofcomputer systemsfor requesting, processing and reporting tests9should improve this response further in thefuture. Most serological investigations are per-formed in batches and testing within the prim-ary unit will depend on individual laboratoryworking practices. Results from this study showthat an average turnround time of under sevendays is possible. When serum samples are des-patched to reference laboratories, the turn-round time is significantly extended. In thissurvey three units achieved an average time of19 days for dispatched samples whilst fourother departments took 21 to 22 days. Thelatter group were encouraged to review theirdispatch procedures as a potential im-provement of two to three days seemed achiev-able.The majority of "clinical syndrome" requests

will not detect any significant abnormality butit is not known whether an average positiveresult rate of 12% is acceptable as similar ana-lyses on serological testing have not been pub-lished. The finding that some units obtainedpositive result rates two to three times greaterthan others may, in part, be because of differentsubjective interpretations of serological results.For example, different laboratories may haveinterpreted a significant positive result as (1)any positive titre to any antigen, (2) a singletitre above "normal", or (3) a rising titre toan organism likely to have caused the illnessspecified. The wide variation in positive resultrates also suggests that improvements in therange and performance of relevant tests andthe ability to gather more precise informationfrom clinicians together with more con-

valescent specimens are all areas ofthe serologyservice which need review.

In biochemistry departments in particular,it has been shown that laboratories responddifferently to the same clinical request.'0 Theproduction ofprompt reliable laboratory resultswill contribute little to patient outcome if thetests performed are clinically inappropriate orredundant and the efficient use of pathologyresources is diminished. This study is the firstto analyse the processing of serology specimensin an area of particular difficulty for clinicalmicrobiologists and their departments. Use ofthe serology service, as applied to "clinicalsyndrome" type problems, has been describedwithin 10 departments in the Oxford regionand practices in need of review and im-provement have been highlighted. This studyis likely to be representative of many serologydepartments across the country and it is hopedthat the findings may stimulate other labora-tories to analyse the procedures and outcomesfor similar areas of their work.

Thanks are due to all medical and laboratory staff within themicrobiology departments of the following hospitals: HortonGeneral Hospital, Banbury; RAF Halton Hospital, Aylesbury;Kettering and District General Hospital, Kettering; MiltonKeynes Hospital, Milton Keynes; Northampton General Hos-pital, Northampton; John Radcliffe Hospital, Oxford; RoyalBerkshire Hospital, Reading; Wexham Park Hospital, Slough;Stoke Mandeville Hospital, Aylesbury; Wycombe General Hos-pital, High Wycombe.

1 Department of Health. The Pathology Services. A Man-agement Review. The Audit Commission for local au-thorities in The National Health Service of England andWales. London: HMSO, 1990.

2 Bareford D, Hayling A. Inappropriate use of laboratoryservices: long term combined approach to modify requestpatterns. BMJ 1990;301:1305-7.

3 Wong ET, Saxena S. Medical appropriateness of laboratorytests. Am J Clin Pathol 1992;97:748-50.

4 Young DW. Improving laboratory usage: a review. PostgradMed J 1988;64:283-9.

5 Peters M, Broughton PM, Nightingale PG. Use of in-formation technology for auditing effective use of labora-tory services. J Clin Pathol 1991;44:539-42.

6 Lundberg GD. Using the clinical laboratory in medicaldecision-making. Chicago: American Society of ClinicalPathologists Press, 1983:viii-ix.

7 Fraser CG, Woodford FP. Strategies to modify the testrequesting patterns of clinicians. Ann Clin Biochem 1987;24:223-31.

8 Marton KI, Tul V, Sox HC. Modifying test-ordering be-haviour in the outpatient medical clinic. A controlled trialof two educational interventions. Arch Intern Med 1985;145:816-21.

9 Wmkel P. Automated decision making in relation to labora-tory test requests. Scandy Clin Lab Invest Suppl 1990;202:120-2.

10 Broughton PM, Worthington DJ. Laboratories responddifferently to the same clinical request. Ann Clin Biochem1989;26:119-21.

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