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Since 1958 pagano-Levin medium (PLM) has been used as an aid in the identification of Candida albicans. However, no statistical analysis of its effectiveness based on large number of random human specimens has been reported. The present study compared PLM (now called Candida test) with Sabouraud's plus antimicrobials and Littman's ox-gall agar without antimicrobials. Of 500 random vaginal samples 24.8 were true positives, 71.9% were true negatives, 2.2% were false positives, and 1.2% were false negatives on PLM. If only samples identified as C. albicans were considered, 95.4% were true positives and 4.6% were false negatives. PLM did not inhibit C. albicans from the vagina. No one medium was found superior to the others for the purpose of isolating and identifying C. albicans. Of the five strains of C. parapsilosis, the only other Candida species isolated, all the samples grew on PLM but most were inhibited on Sabouraud's medium plus antimicrobials.

The detection of psychiatric illness is increasingly becoming the responsibility of non-psychiatric physicians. As part of a large scale epidemiological survey of psychiatric illness in a metropolitan area, primary care M.D.s and osteopaths were compared for their ability to detect psychiatric illness. Although neither group of physicians detected as much illness as patient self-assessments revealed, osteopaths detected significantly more psychiatric illness than M.D.s. When, however, physician and patient reports of illness were juxtaposed, to determine concordance, M.D.s and osteopaths showed similar degrees of overall accuracy. Osteopaths tended to detect more true positives, while M.D.s detected more true negatives. Different practice and social characteristics were not found to account for practice differences in physician rates of psychiatric illness detection. Osteopaths appeared to be performing at least as effectively as M.D.s in a first line of defence against mental illness.

Two radiologists individually gave ‘blind’ diagnoses of benignancy or malignancy to 145 radiographic representations of gastric ulcers, all with gastrectomy histological proof of benignancy or malignancy. A radiological diagnosis of malignancy was shown to be 98·6% reliable. A diagnosis of benignancy was less reliable (85·4% true positives) but this was a surgical series containing thereby an abnormally high proportion (over a third) of malignant ulcers. A correct diagnosis was made in 99·5% of the proven benign ulcers, but in only 68·6% of the proven malignant ulcers. Analysis of the pathology reports on the malignant ulcers has shown that it was mainly those arising on the basis of pre-existing benign ulcers (i.e. secondarily malignant ulcers) that were wrongly diagnosed radiologically, thus suggesting that they have a fundamentally different radiographic appearance from that of primarily malignant ulcers. It was then found that the ulcers could be divided into three simplified radiological types based on their in-profile appearances: type 1 (projecting), type 2 (intraluminal) and type 3 (so shallow as to be neither projecting nor intraluminal). Statistical association with the histological types led to the following conclusions: (a) radiological type 2 or 3 ulcers should be diagnosed as almost certainly malignant (usually primarily malignant) and (b) radiological type 1 ulcers are almost always benign but should be followed up until healed because the rare secondarily malignant ulcers are also usually of this type.

Ten radiologists were shown a series of 10 normal and 10 abnormal chest films under two viewing conditions: a 0.2-second flash and unlimited viewing time. The results were compared in terms of verbal content, diagnostic accuracy, and level of confidence. The overall accuracy was surprisingly high (70% true positives) considering that no search was possible. Performance improved as expected with free search (97% true positives). These data support the hypothesis that visual search begins with a global response that establishes content, detects gross deviations from normal, and organizes subsequent foveal checking fixations to conduct a detailed examination of ambiguities. The total search strategy then consists of an ordered sequence of interspersed global and checking fixations.

Sir .—We agree that the Limulus assay is suitable for detecting endotoxemia, but contend that it is not of value in detecting Gram-negative bacillary sepsis or bacteremia. Only when the preparation and sensitivity of Limulus lysate and extraction procedure of endotoxin have been standardized can the clinical usefulness of this test be finally determined. Ultimately the physician will have to ask, "Will this test assist me in determining the diagnosis and management of my patient's condition?" If the number of false positives and false negatives is equal to or greater than the number of true positives or true negatives (based on culture-proved infections), then the test will offer no advantage over the present clinical and laboratory diagnosis of infection, and may indeed be another cost-accountable expense for the patient. To date, the published studies are only suggestive of clinical value of the assay. Further studies in large and high-risk populations

Although new tests for syphilis, as well as new applications of standard tests, continue to appear, the usefulness of several of these procedures has not been determined. When the Fluorescent Treponemal Antibody-Absorption (FTA-ABS) test is used to screen for syphilis, the proportion of positive results that are true positives decreases. The value of modified FTA tests in the diagnosis of neurosyphilis and congenital syphilis remains unproved. Although not studied as extensively as the standard tests, several newer methods--the direct fluorescent antibody test for Treponema pallidum (DFATP), the Rapid Plasma Reagin (RPR) card test, and the microhemagglutination test for T. pallidum (MHA-TP)--may have certain advantages. To be of optimal diagnostic value, tests for syphilis must be selected according to the clinical situation.