The Datatree costing project in Wales has provided the Welsh pathology laboratories with a standard costing package that allows pathologists to understand how their own laboratory's test costs are compiled. The software provides answers to the question "what if? ..." and shows instantly the effect of salary or consumable cost alterations. Resource management at a laboratory level is enhanced by a greater knowledge of costs, particularly in relation to volumes of work. Perhaps this is one of the stepping-stones across the river to the "open market." In the United Kingdom NHS any information of this kind must be regarded as invaluable.

SUMMARYA prospective study of genital infection was conducted in four inner-city family–planning clinics. Fifteen per cent of routine attenders had symptoms and signs of vaginal infection and many more women attended primarily because of symptoms. Among the women with both signs and symptoms, 70% had positive laboratory findings, Trichomonas vaginalis, Candida albicans and bacterial vaginosis being equally prevalent. Measurement of vaginal pH in the clinic was the single most useful clinical finding for directing empirical therapy. Among patients with a discharge confirmed on examination and an abnormally high pH, 72% had either T. vaginalis or bacterial vaginosis. Neisseria gonorrhoeae was isolated from 4% of women with, and 1% of those without, symptoms. We believe that it is worthwhile to investigate patients presenting to family-planning clinics with vaginal symptoms. No single specimen was found ideal for all pathogens, a cervical swab is better for gonococci and also for T. vaginalis but a vaginal swab is needed for Candida and bacterial vaginosis.

During a study of genital infection in inner-city family-planning patients we examined 452 women for Chlamydia trachomatis. The prevalence of infection was 7.3%. There was no significant difference between patients attending because of genital symptoms and those who were attending for routine family-planning advice. Infection was found to be correlated with five main demographic parameters; age less than 25, no stable partnership, hormonal contraception, nulliparity and West Indian Ethnic origin. Using these parameters a simple scoring system was devised which allowed a high-risk population to be defined in whom screening would be economically justified.

special attention to clinical applica- tions.

Ultracentrifugation was used to separate IgG from IgM in serum samples from children after pertussis vaccination or infection and the fractions were examined by indirect haemagglutination (IHA) and complement-fixation (CF) tests. IHA detected pertussis-specific IgM and IgG but CF detected only IgG which appeared to be of a different subclass from the IHA IgG. The IgM titres were higher after infection than after vaccination but the reverse tended to apply to the IgG titres. Little IgM or CF IgG was detected 5 months after a dose of vaccine, but the IHA IgG persisted longer. Vaccinated children who were subsequently infected showed IgM and CF IgG responses similar to those of unvaccinated, infected children but the IHA IgG titres reached much higher levels.

Indirect haemagglutination (IHA), agglutination and complement fixation tests (CFT) for Bordetella pertussis antibodies were compared on paired sera from 52 suspected cases of whooping cough and single sera from 83 children with no recent history of whooping cough. All three tests detected serotype antibodies 1, 2 and 3, but the IHA test was the most sensitive; in seven cases it was the only test to show a rise in titre. It is recommended, particularly with vaccinated children, that the serological diagnosis of whooping cough should be based upon a rise in titre. There should be a gap of at least 2-4 weeks between serum samples, depending on the age and vaccination state of the child. The CFT appears to detect a different antibody from that detected by the other two tests, and in three cases it was the only test to show a rise in titre.