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KIDNEY BROKERAGE

SiR.—The questions raised by Dr Bach (Nov 10, p 1102) are veryimportant for medicine in the developing countries and are ofconcern to those working in transplantation in the Middle East. Ifeel that your accompanying editorial (p 1081) has not fullyconsidered the implications of the last two paragraphs in Bach’sletter. To compare the bribing of a policeman and the procurementof kidneys is not, I think, valid. The bribing of policemen is illegal inmost countries, whereas the taking of a kidney for organ donation isnot so clearly categorised. I agree that the taking of kidneys for profitwould be totally repugnant, but I am not yet convinced that somefinancial inducement of a potential donor is ethically unacceptable.I would like to hear informed discussion on this point.

10 000 to 20 000 renal transplant operations are carried out eachyear. Probably fewer than 5% of patients worldwide who have renalfailure are offered this therapy. Most programmes are based on theavailability of cadaver organ donations. The procurement ofcadaver kidneys is considered at best socially unacceptable inIslamic societies, and it is immoral in Buddhist societies. Thealternative to living related donor transplantation in the MiddleEast is to import cadaveric kidneys from Western countries or tosend patients to the United States or Europe for a cadaver

transplant. Both these procedures are expensive and generateconsiderable profit for transplant centres.

I am very unsure of the duties of a doctor, confronted by a patientwith renal failure who has produced an unrelated donor of suitableblood group and tissue type, who is asked for advice for both thedonor and recipient. Such patients are already dealt with in othercentres and I think that the matter deserves full discussion to try toensure that not only are doctors working in an ethical fashion butalso that each patient is receiving optimum treatment.

Ibn Al Bitar Hospital,Baghdad, Iraq PETER J. LITTLE

PRELIMINARY EVALUATION OF AN ENZYMEIMMUNOASSAY TEST FOR THE DETECTION OF

CHLAMYDIA TRACHOMATIS

SIR,-The growing number of requests for laboratoryconfirmation of Chlamydia trachomatis infections, mainly fromdepartments of genitourinary medicine, has greatly increased thelaboratory workload. At present, diagnostic methods centre aroundisolation in cell cultures or detection of elementary bodies in smears,both of which are laborious when large numbers of specimens are tobe examined.We have done a preliminary evaluation of a solid-phase enzyme

immunoassay (EIA) to detect C trachomatis antigen in swabs fromthe genital tract of 237 females and have compared the results withthose obtained by the routine cultural methods in use in the Oxfordand Leeds virology laboratories.Two swabs were collected from the same genital site; one

according to the routine manner used by the laboratory and theother according to the instructions in the EIA diagnostic kit. TheEIA test was carried out according to the manufacturer’sinstructions. The culture methods of the two laboratories weresimilar except that in Oxford swabs were broken off into Ctrachorrtatas transport medium and frozeJ.1 in liquid nitrogen untilinoculation onto cultures, whereas in Leeds swabs were broken offin transport media and held at 4°C until inoculation onto cultureswithin 24 h of collection; rarely, a specimen was held at - 70’Cbefore being inoculated. In Oxford, cultures were examined forinclusion bodies after 72 h incubation, but in Leeds the routineexamination was carried out after 48 h incubation or, occasionally,after 72 h.

Specimens from 12 patients (6 in Oxford and 6 in Leeds) are notincluded in the analysis because they were considered unsuitable forcomparison due to toxicity or contamination of the tissue cultures.Results on the remaining 225 samples are shown in the table.

If culture methods alone had been used in Oxford, 16 of 123(13’ 00/0) samples would have been positive; if EIA only had beenused, 34 (27 - 6%) would have been found. At Leeds, 29 of the 102specimens (28-4%) were positive by culture only and 32 (31 -4%)

RESIT 1,TS OF TESTS BY ENZYME IMMUNOASSAY AND CULTURE FOR

C TRACHOMATIS ON GENITAL TRACT SWABS COLLECTED FROM 225FEMALES

were positive by EIA alone. The combined Oxford and Leedsresults give a co-positivity of 88-9% and a co-negativity of 85 6%,taking culture as the reference method. I

There were 26 specimens reactive in the EIA from which noisolate was obtained, and Jones et al, comparing an EIA test withculture for C trachoma tis) refer to such a group as "false positives".It may, however, be misleading to compare the number of positives/obtained in one test with that in another test when neither- is knownto represent an absolute indication of infection. An "EIA positive/culture negative group" may contain false positives; but it is equallypossible that cultural techniques have failed to isolate C trachomatis,especially since blind passage was not done. Problems of

contamination, insensitivity, and toxicity in cultural techniques arewell known, and transportation and freezing may decrease theviability of the organism; these factors may have contributed to theOxford findings of 19 swabs positive by EIA, but negative byculture. The lack of a "specimen control" in the EIA kit (beads notcoated with anti-C trachomatis serum), which would presumablyhelp to detect non-specific reactions, is a matter which should beconsidered if it is suspected that some specimens-give false positivereactions.The EIA method is adaptable to large-scale routine testing and

would eliminate problems associated with tissue culture.This preliminary investigation was done on swabs from females;

however, provided the EIA method compares as favourably asculture on samples from male patients, and provided that the higherEIA positivity rate is not a spurious finding, this test will go a longway to helping a laboratory offer an improved service.

We thank the clinicians who made the specimens available, the laboratorystaff who did the technical work, and Abbott Laboratories Diagnostic Divisionfor the EIA diagnostic kns.

Virology Department,Public Health Laboratory,Leeds LS15 7TR M. H. HAMBLING

Department of Virology,John Radcliffe Hospital, Oxford J. B. KURTZ

1 Buck AA, Gart JJ Comparison of a screening test and a reference test in

epidemiological studies I Indices of agreement and their relation of prevalence. AmJ Epidemiol 1966, 83: 586-92

2 Jones MF, Smith TF, Houglum AJ, Herrmann JE. Detection of Chlamydia trachomatisin genital specimens by the Chlamydiazyme test J Clin Microbiol 1984; 20: 465-67

MICROALBUMINURIA AND DIABETIC RETINOPATHY

SIR,-Diabetic nephropathy accounts for >30% of deaths in

insulin-dependent diabetics (IDDs), and diabetic retinopathy is thecommonest cause of blindness in the working population. IPersistent ’Albustix’ positive proteinuria signals the onset ofirreversible clinical diabetic nephropathy. A raised urinaryalbumin excretion rate (AER), but below the level of albustixdetection (microalbuminuria), predicts the development of clinicalnephropathy.3 Diabetic retinopathy is almost always present inassociation with overt nephropathy, but little is known about itsrelation with microalbuminuria. We report a study of blood glucose,arterial pressure, other microangiopathic complications, andmicroalbuminuria in patients with IDD.