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principle is simultaneous comparison of results of a seriesof patients (at least 12) within the therapeutic range withthe unknown and standard preparation to determineresults equivalent to the standard therapeutic range-i.e., 15-30% activity (1-7 to 3 times ratio). An exampleis given in table ill. It is quite easy in this way to obtaina close approximation to the equivalent therapeutic rangewith human-brain preparations, since they show similarsensitivity to the clotting factors. Difficulty is encounteredwith some of the animal extracts, particularly with thoseinsensitive to factor vil. Insensitive reagents should notbe used, and the suggested method of testing the com-mercial reagents with lyophilised plasma deficient infactor vn may in future offer a useful method of screeningunsuitable animal preparations before they are marketed.In addition to not disturbing established practice in aparticular hospital, the standard scheme provides a checkon the variations of successive batches of home-made orcommercial preparations as well as a constant check againstdeterioration, which happens sooner or later with all

types of thromboplastin. In this way we have linked upwith a number of well-established schemes in hospitalssuch as the Sheffield city hospitals, and Coventry hos-pitals. The standard schemes also allows the use of thesame therapeutic range as those employed in a number ofcurrent therapeutic trials. The nation-wide standardscheme uses an extremely small quantity, less than theroutine supplies of a single large hospital. This is there-fore an extremely economical way of producing uniformityof control on a large scale.The cost of the service is a fraction of that of the

commercial reagents formerly used in the ManchesterRegion alone. The saving over the whole of the routinesupply area is considerably more. Economy, however,was never the purpose of the scheme and was probablythe least important principle. There is no fundamental

objection to the use of satisfactory commercial prepara-tions, provided that they conform to a number of criteria.Each batch, however, should be matched against anindependent standard and should be sufficiently sensitiveto the coumarin-affected clotting factors. Our standardservice is based on the provision of the best type ofmaterial for measuring human clotting factors-i.e.,human tissue. A standard for use abroad producedcommercially would have to be an animal product. Itcould be matched against our own preparation and shouldsatisfy the following criteria:

(1) Adequate sensitivity to coumarin-affected factors,particularly factor vil.

(2) Ratio of approximately two to three times for the

therapeutic range.(3) Stability on storage.(4) Good end-point in laboratory test.(5) Ease and reliability of preparation of the liquid extract,

if issued in dried form.

(6) Successive batches should be monitored against thestandard.

Thus the experience acquired in clinical practice withour reagent as well as our large-scale monitoring systemcould be used in support of any new standard. Inter-national standardisation of thromboplastin reagentswould be a great advantage not only to patients on anti-coagulant treatment but also to pathologists, hxmato-logists, and other clinicians, in addition to the manycommercial companies which manufacture laboratoryreagents. The Manchester scheme could therefore pavethe way to this international standard.

Round the World

CanadaWhen we came here my wife left her chilblains behind, and

has not had one since. Wintering in the Yukon Territory, wesaw frozen noses from time to time and occasionally frostbite inthe elderly prospector who had had the misfortune to get hisfeet wet while he was out on the trail with his dogs. But of thefamiliar British chilblain we saw nothing. They told us thatthat winter was a mild winter, the temperature falling only to63°F below zero; in a severe winter the thermometers might godown to 80°F below. Old-timers would take photographs oftheir thermometers. One man had a picture of the metalchimney of his cabin coated with ice and smoke coming out ofthe chimney; he said that the fire was roaring up the stove-pipeat the time.

Tanzania

The for-some-time rtimoured upgrading of Dar es SalaamMedical School to a faculty of the university is now scheduledto take place in July next year, and plans are being made,rather against the clock, for a considerably expanded intake ofmedical students. This at least will be a welcome event forthe School, which at present is limping slightly after Presi-dential rustication of an entire year’s intake and of a part ofthe remainder of the student body last year. But expandingimplies increased staff, and one wonders how easy it will beto attract them to Tanzania in view of the public image itmust be presenting after its sweeping nationalisation moves-moves which one hopes, rather without conviction, were notas hurriedly planned as they were announced.Whether and how teaching will be divided between the

present school adjacent to the teaching hospital in Dar itself,and the university 8 miles away, remains to be decided; theadvantages of keeping preclinical and clinical sides togethervie with the disadvantages of depriving the medical studentsof campus life with the other disciplines.

U.S.A.Clinical pathologists and their organisations have given

much time to ensuring the accuracy of laboratory tests bystandardisation and quality control; and the problems wereaired at a recent Senate committee. In the U.S.A. only a fewStates have comprehensive legislation covering the licensing,inspection, and control of diagnostic medical laboratories;others require certain training standards for those operatingsuch laboratories; others ensure control only of some invest-igations of public-health importance (such as serological tests);and others have attempted by voluntary means to improveresults. 1 So far each State has hitherto been concerned to

safeguard the interests of its own citizens, so, even in Stateswhere legislation exists, anyone, trained or not, may opena laboratory and do business, provided the services are confinedto

" mail order " clinical pathology for out-of-State physicians.In other States, such a laboratory can offer its services to localdoctors, perhaps undertaking to do all tests required in apractice for a small monthly fee. The laboratory may be" fronted " by a physician, who may lend his name for a feeor for a share of the profits. Even in a State where clinicallaboratories are subject to some control, there is nothing toprevent a physician shipping his specimens to some out-of-Statecut-price laboratory.The Senate committee heard much disquieting evidence. Dr.

D. J. Sencer, of the National Communicable Disease Centre,stated that about a quarter of the laboratory tests processedeach year in the U.S.A. were erroneous. A New York

laboratory, suspended for inaccurate reporting, had been find-ing hormones in distilled water coloured by a yellow dye tosimulate urine: it was doing over 150,000 tests a year. Four out

1. Bauer, H. Hospital Practice, 1967, 2, 67.

494

of every ten laboratories tested in Illinois failed to determinethe correct blood-group and rhesus factor; nine out of everyten laboratories tested in Pennsylvania were unable to test

accurately for parasites in stool specimens. Others, it seems,were unable to detect blood artificially added to urine; and, inCalifornia, where legislation controlling laboratories isadvanced, it was found that 600 slides of cervical smears hadbeen sent by one physician to a laboratory in New York andwere never examined-though reports were returned. Equallyalarming evidence was given by Dr. Morris Schaeffer, directorof the New York City Laboratories.

Senators Javits and Murphy intend to introduce bills intoCongress to deal with some of the urgent problems, but theseare extremely complicated. The enormous expansion in

laboratory tests, in type, in number, and in complexity, iscontinuous. Bauer 1 refers to a " national laboratory crisis ",and this is hardly an exaggeration. He estimates that the presentcall in the U.S.A. for 9100 additional medical technologists tocope with the present load is quite insufficient, and he believesthe number of tests asked for will more than double in the nextdecade. Not only are many more medical technologists needed,they will have to be much better paid. It will be interesting tosee how the Federal Government, in its new-found interest inmedical matters, will rise to the crisis.

VietnamShe was just another bit of flotsam from the civil war with a

big wound in the left costal margin. The difference was thather clothing had been carefully cut away leaving the bit thathad been carried into the wound and furthermore, no-oneseemed keen to go very near her. Our portable X-ray machinegave us the answer-an unexploded grenade in the left upperquadrant. Never one for heroics I wished I had stayed at home;fortunately it lifted out without too much difficulty, but thetheatre seemed very empty and quiet as I made the cut to getit. The loud report from the demolition experts outside wasthe most comforting sound I had heard for a long time.

Zambia

Zambia now has its own medical journal. Under the

editorship of Dr. J. C. Davidson, the Medical Journal ofZambia, which appeared last month for the first time, aims topublish clinical articles of local interest and also isolated inci-dents reported by doctors sequestered in " bush " stations.Dr. Davidson is medical specialist at Lusaka Hospital, and hewill no doubt bring to his new task the enthusiasm for which heis renowned throughout the country. The assistant editor isDr. A. M. Hassim, the gynaecologist and obstetrician.

Public Health

MULTIPLE-SCREENING TESTS IN GLASGOWMEN AGED OVER FORTY-FIVE YEARS

WILLIAM A. HORNE

C.B.E., M.D. Glasg., D.P.H.MEDICAL OFFICER OF HEALTH

JOHN CLARKM.B. Glasg., M.R.C.P.G., D.P.H.

PRINCIPAL MEDICAL OFFICER

WILLIAM J. PATTERSONM.B. Glasg., D.P.H., D.I.H.DIVISIONAL MEDICAL OFFICER

HEALTH AND WELFARE DEPARTMENT, GLASGOW

Summary A multiple-screening clinic for men overforty-five years of age was held in Glasgow

in July, 1965. 4372 volunteers presented themselves forexamination of height and weight, blood-pressure,haemoglobin level, vision, urine for glucose, and radio-graphy of the chest.

INTRODUCTION

IN Glasgow, where the incidence of pulmonary tuber-culosis has remained higher than in most other Britishurban communities, the mass-radiography service operatesthroughout the year; in 1957 a very successful campaignresulted in earlier treatment for many patients and a sub-sequent fall in the incidence of the disease. The greatestprevalence of pulmonary tuberculosis has recently beenin older men. At the age of forty-five, men enter an " atrisk " period when an increasing proportion have defectswhich may be symptomless. This sub-group of the

population is likely to profit from a battery of screeningtests designed to detect presymptomatic disease. Wedecided to carry out this experiment in the multiple screen-ing of men aged over forty-five years during a period ofreduced departmental pressure, and when a considerablepart of the population would be on holiday. The periodselected was the Glasgow Fair. Evening sessions wereheld commencing at 5.30 P.M. on the nine week-days fromTuesday, July 20 to Friday, July 30, 1965. The localmedical committee welcomed the experiment and askedthat the final report be forwarded to them for discussion.

Only one centre was used at the department’s headoffice where there are clinics in the basement, with acontinuous series of rooms off a corridor 65 yards long.Thus, the men could enter at one end of the building andmove from stage to stage, leaving at the other end. Themass-radiography service cooperated by providing a

mobile X-ray unit to work with the one in the health andwelfare department.The tests selected were for height and weight; blood-

pressure ; for glycosuria; haemoglobin readings in selectedmen; vision for those who did not already wear spectacles;and X-ray of the chest. As there was no way of knowinghow many men would come forward we decided to use

only limited publicity. Before the campaign started,general practitioners were sent a circular, and eachreceived copies of the records of his patients. Each of thescreened men was advised either that the results were

satisfactory within the limits of the tests or that he shouldconsult his doctor.

In the screening tests, the following significant levelswere accepted:

Height and weight were measured with men clothed, wearingboots or shoes, but without overcoats or hats or caps. Theaccepted standards of weight for height were taken from Cony-beare’s Textbook of Medicine.1 Men were referred to theirgeneral practitioners on account of underweight or gross over-weight-underweight being judged to be 15% below thestandard weight for height, and overweight more than 28 lb.(12’7 kg.) above the accepted standard.

Blood-pressure.-Men were referred to their doctors wherethe diastolic pressure was 100 mm. Hg or over.

Urine testing was carried out with the use of ’ Clinistix’;when a result was not clearly negative the urine was tested bymeans of ’ Clinitest’ tablets. Only when the ’ Clinitest’ waspositive was the man referred to his own doctor.Hamoglobin was estimated by means of an M.R.C. Grey-

wedge’ photometer, and men with haemoglobin below 12’4 g.per 100 ml. or 85 % were referred to their doctor. Thestandard used was Haldane 100% = 14-6 g. per 100 ml. Experi-ence on the first evening indicated that the haemoglobin testwas holding up the passage of men through the centre. There-after, the doctors taking blood-pressure selected a proportionof the men for hxmoglobin estimation.

Vision was tested by means of a ’ Keystone ’ screener. The1. Conybeare, J. Textbook of Medicine; p. 848. Edinburgh, 1949.