TORCH Screening: Time for Abolition?

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TORCH screening: time for abolition?W . L. Lim and D. A. Wong

AbstractThe acronym TORCH (toxoplasma, rubella, cytomegalovirus, herpes simplex virus) was intro-duced to highlight a group of agents which cause congenital and perinatal infections. TORCHscreening is now widely requested by clinicians investigating suspected cases of congenital an dperinatal infection. There is concern that such requests ar e inappropriate and requests fo r inves-tigation should be targeted more specifically. The prevalence of TORCH infect ions in HongKong are examined in this study. Toxoplasmosis is a rare infection in Hong Kong with aseropositivity rate of only 2.4% amo ng wom en of child-bearing age; 87.5% of women of child-bearing age are already seropositive for cytomegalovirus (CM V) and therefore m ost cases ofcongenital CM V infection are l ikely to result from maternal reinfection which carries a muchlower risk of severe congenital abnormalities. Congenital rubella infections still occur each yearin small num bers. N eonatal herpes simplex virus (HSV ) infection is very rare inHong Kon g. It isapparent that requests fo r TORC H screening has been over-ordered and clinicians should beencouraged to send ap pro priate specimens for spec ific tests depending on the clinical fe atures ofth e individua l case.K e y w o r d s : TORCH; Seroprevalence; Con genital infections

IntroductionTh e acronym TORCH was int roduced in 1971 byNahmias et al. to highlight a group of agents whichaffect th e foetus an d newborn, namely Toxoplasmagondii, rubella virus, cytomegalovirus (CMV), an dherpes simplex virus (HSV).1 These ag ents often pro-vide a similar clinical picture which include one ormore of the following clinical signs: low birth weight,prematur i ty , purpura , jaundice , anaemia , micro-c e p h a l y / h y d r o c e p h a l y , c e r e b r a l ca lc i f i ca t ion ,c h o r io r e t i n i t i s , c a t a r a c t s , m i c r oph t ha l mi a , a ndpneumonitis . TORCH screening is now widely re-ques ted by c l in ic i ans inves t iga t ing infant s andpr e gna n t wome n fo r c onge n i t a l , pe r i na t a l a n dneonatal infections. There is concern among micro-biologists that such requests are often inappropr ia tean d that resources would be better utilized if requestsfor investigation were targeted mo re specifically2. W edecided to conduct a study in order to assess thefrequency of congenital TORCH infections in HongKong.

Virus U nit , Queen Mary Hospital , Pokfulam , Hong KongW . L. Lim, MRCP ath, FRCPAD. A. W ong , MB , ChB, M ScCorrespondence to: Dr D . A. W ong

Patients and specimensAll requests fo r toxoplasma serology, whether as par tof th e TORCH screen or otherwise, were docume nted,as were al l requests for CMV antibody status for theperiod from 1 July 1992 to the 30 June 1993. All re-quests for toxoplasma serology were initially testedfor specific IgG by indirect immu nofluorescence an dpaired sera were requested to detect rising antibodytitre. Those wit h a titre of 80 or greater were tested forthe presence of specific IgM by immunofluorescence.Th e seroprevalence rate fo r women of child-bearingag e were compiled from TORCH requests taken fromwomen who presented with ma ternal il lness, intrau-terine growth retardation, abortion, prema ture ru ptureof membrane (PROM) and foetal distress. Sera fo rCM V antibody status were first screened for the pres-ence of CMV antibodies by complement fixation tests.Those which were negative by com plement fixationtest were retested by enzyme-linked immunosorbentassay (ELISA) (Behring) for the presence of specificIgG. All requests for CMV cul ture fo r urine, salivaand throat swabs collected from neonates less th an 14days old were documented over the same period.Diagnosis o f rubella infection was made when thereis a r is ing ant ibo dy t i t re de tec te d by h aem ag-glu tina tion inhibition tests and tha t specific IgMantibody is detectable by ELISA (Abott an d Pasteur).

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Table 1. Toxoplasma serology requests (1 July 1992 to 30 June 1993).Clinical presentation No. PosIUGR/SGA/LBWlUD/AbortionNeonatal symptomsPrematurityPROM/leakage/foetal distress/preterm labourMaternal fever and illnessPostnatal symptomsBone marrow transplantAML/NHL/other haematological conditionsHIV+veOthers/no details availableTotalWomen of child-bearing age

IUGR Intrauterine growth retardationSG A Small for gestational ageLB W Low birth weightIUD Intrauterine deathPROM Premature rupture of membraneAML Acute myeloid leukaemiaNHL Non Hodgkin's lymphoma

31024 54931437933

20613741

162237

2086667

6810320

1122

15137216

1.933.262.022.092.5305.331.454.879.255.483.452.40

Herpes simplex virus infection is diagnosed by virusisolation. A search was carried out on our positiverecord files for the years 1986 to 1992 for cases ofconfirmed congenital rubella an d neonatal herpessimplex virus infection.

were sy mp tom atic adults. 1,303 (62.5%) were requestsfor TORCH screening of which only 29 (2.22%) sam-ples had IgG antibody against toxoplasma, none ofwhich ha d current infection. The seropositivity rateamong women of child-bearing age was 2.4%.

ResultsToxoplasmosisFor the period from 1 July 1992 to 30 June 1993, theVirus Unit received requests fo r toxoplasma antibodytesting from 2,086 patients (Table 1). Only 72 (3.45%)were positive for IgG antibody against toxoplasmawhich is indicative of past infection. IgM antibodieswere dem onstrated in only two patients both of whom

Table 2. Requests for CMV isolation from neonates lessthan 14 days of age (1 July 1992 to 30 June1993).

Clinical presentation Total no. PosIUGR/SGA/LBWNeonatal symptomsPrematurityPROM/leakage/foetal distress/preterm labourOthers/no details available

16623 113416

165

2411

2Total 712 10

Cytomegalovirus i n f e c t i o nFor the period from 1 July 1992 to 30 Jun e 1993, therewere 953 requests for CMV serology of which 887(93.1%) ha d demonstrable CMV antibodies, whichshows that Hong Kong has a high prevalence of CMVinfection. 161 out of 184 (87.5%) specimens taken fromwome n of child-bearing age (16-40 years) were posi-tive for CMV antibodies. Over th e same period, urine,saliva or throat swabs specimens were received from712 neonates less than 14 days old for CMV isolation(Table 2). Only 10 (1.4%) were positive for CMV bythe CMV DEAFF test. Ho w many, if any, of theseinfants had cytomegalic inclusion disease was notknown. Serological testing for CMV antibodies usingcomplement-fixation tests were carried out on sevenof these infants (Table 3), only in one case (patient4)was a significan t rise in CMV antibody titre demon-strated.RubellaA small num ber of infan ts with congen ital rubellasyndrome are born each year (Table 4). For the periodfrom 1 July 1992 to 30 June 1993, of the 4,145 reque stsfor rubella antibody testing by haemagglutination-


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308 J Hong Kong Med Assoc Vol. 46, No. 4, December 1994

Table 3. Serological results (by complement-fixationtests for CMV antibodies ) and clinical cond itionof the 10 neonates who we re excreting CMV intheir urine within 14 days of birth.

CMV antibody titresPatient 1st titre 2nd titre Clinical condition12345678910

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Lim & Wong: TORCH screening 309

t h a t 90% of nulliparous women and 93% of multipa-rous women of child-bearing age were positive ofrubella antibody.7 This showed tha t despite the im-p l e m e n t a t i o n of selective rubella vaccination inpr imary six school girls in 1978 and the extension ofimmunization to postpartum women who are foundto be seronegative while attending antenatal clinics,asizable percentage of women of child-bearingag e werestill susceptible to rubella infection. Therefore it is ofutmost importance that all women are immunizedagainst rubella. A ll suspected contacts with rubella,or any clinical symptoms of rubella infection in preg-nancy should be investigated by rubella serology.From our data, neonatal herpes is not an importantproblem in Hong Kong. Neonatal herpes is best diag-nosed by the virus culture of specimens taken fromaffected sites such as vesicle fluid, saliva, mouth swabsand CSF rather than by serology.2To conclude, with th e exception of rubella, TORCHagents are not as common a cause of congenital infec-tion in Hong Kong as in other developed countries.W e feel that th e test had been over-ordered. The con-cept of a common presentation of congenital infection(TORCH syndrome) and a common investigativep a t h w a y (TORCH screening) should be actively dis-couraged. Instead, clinicians should be encouraged tosend specimens fo r specific tests depending on theclinical features of individual cases. For example,cataracts and cardiac lesions are common in congeni-ta l rubella but not with any other TORCH agent:cerebral calcification is extremely rare in rubella and

is only widely distributed in toxoplasmosis: deafnessis associated only with rubella and CMV infect ion.Thus appropriate samples such as urine, saliva andvesicle f lu id should be cultured for CMV and HSV inthe case of suspected congenital CMV or HSV infec-tion. Neonatal sera are useful for the diagnosis ofcongenital rubella and toxoplasma infection, but oflittle value in the diagnosis of neonatal CMV an dHSV infections.

References1. N a h m i a s A J, Josey W E , Naib Z M , Freeman M G ,Fernandez RJ, Wheeler JH . Perinatal risk associatedwith maternal herpes simplex infection. Am J OhstetGynecol 1971; 110: 825-37.2. Public Health Laboratory Service. TORCH screeningreassessed. London: PHLS, 1990.3. Ludlam G B, Wong KK, Elaine Field C. Toxoplasmaantibodies in sera from Hong Kong. J Hyg Camb 1969;67: 739-41.4. Hal l S. Congenital toxoplasmosis. BMJ 1992; 305: 291-7.5. Fowler KB , Stagno S, Pass RF, Britt NJ, Boll TJ , A lfo rdCA. The outcome of congenital cytomegalovirus infec-tion to mate rna l an t i body status. N Engl J Med 1992;326: 663-7.6. Stagno S, Whitley RJ . Herpes infec t ions of pregnancy,

part I: cytomegalovirusand Epstein-Barr virus infec-tions. N Engl J Med 1985; 313: 1270-4.7. Lim WL. Seroimmunity to measles, mumps, rubel laand poliomyelitis in Hong Kong. Hong KongJ Paed i a t r1992; 1: 34-40.

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TORCH Screening: Time for Abolition?