Diagnosis of urinary tract infections : aspects of quality assurance and communication of concepts

Urinary tract infection (UTI) is a common disease; most cases are managed in primary health care (PHC. Dipslide (a type of urine culture test designed for point of care testing) is used in PHC in Sweden for the diagnosis of UTI. The results in an external quality assessment programme initiated in 1993 for dipslide did not improve over the years. Thus, a comparison between Uricult Trio® (a type of dipslide) and conventional urine culture was made, in this 32 % of the dipslide results diverged from the result obtained by conventional urine culture.

The effect of two training methods on performance of dipslide and conventional urine culture in PHC was also studied. The error rates decreased from 30-39 % to 13-19 % after training.Further, four chromogenic media for urine culture were compared to routine media for urine culture. A total of 1200 urine specimens were included. Evaluation using quantitative culture of reference strains was also done. There were only minor differences in isolation rate between the different media for Gram negative bacteria. Except for enterococci, Gram positive bacteria grew poorer on the chromogenic media than on blood or CLED agar. The isolation rate on any single medium was 92 - 96 % of the total Ndegrees of isolated strains (MacConkey excluded). The increase in isolation rate after two days of incubation was small on all media, 97 - 100 % of isolates were recovered after one day of incubation.

These findings prompted studies concerning the communication of knowledge on UTI. The aim was to specify a categorical structure for the knowledge domain of UTI using grounded theory methodology. Swedish reference texts and patient records from visits for UTIs in primary healthcare were studied. In total 560 concepts were found. Four major categories: microorganism, disease, healthcare, and host, plus 58 subordinate categories were developed. Relations between concepts were defined. In an accompanying project this categorical structure was used in a decision support system for Uricult Trio® Both the needed level of granularity and the emphasis of different characteristics of a given concept differ between medical domains, e.g. general practice and clinical microbiology. In short: The concepts used in communication are adapted to the activity one is currently engaged in. For example, the concepts used in technical diagnosis at a clinical bacteriology laboratory must be translated to taxonomical concepts at a useful level before being communicated to the clinician. Another consideration in communication is the intended function of a statement. Authors seldom explicitly express if a statement is intended as a defining criterion, recognizing criterion, or characteristic. This has implications on statistics, health care and research.

These studies concluded that dipslide culture is only suitable for diagnosis of UTI caused by E. coli in high colony counts or to exclude UTI. Further, the most important factor to improve the quality of dipslide culture in PH is establishing cooperation between clinical microbiology and point of care testing sites to develop a training and quality assurance programme. Finally a strategy for quality assurance of dipslide in PHC is suggested.

List of scientific papers

I. Aspevall O, Kjerstadius T, Lindberg L, Hallander H (2000). "Performance of Uricult Trio assessed by a comparison method and external control panels in primary healthcare. " Scand J Clin Lab Invest 60(5): 381-6
https://pubmed.ncbi.nlm.nih.gov/11003257

II. Aspevall O, Forsum U, Kjerstadius T, Hallander H (2000). "Evaluation of two methods for improving quality of diagnosis of bacteriuria by culture in primary healthcare. " Scand J Clin Lab Invest 60(5): 387-93
https://pubmed.ncbi.nlm.nih.gov/11003258

III. Aspevall O, Osterman B, Dittmer R, Steen L, Lindback E, Forsum U (2001). "Performance of four culture chromogenic urine culture media after one and two days incubation compared with reference media." (Submitted)

IV. Aspevall O, Karlsson D, Forsum U (2001). "Building a concept system to structure the contents of a decision support system- a grounded theory study of concepts in the knowledge domain of urinary tract infection." Medical Informatics and The Internet in Medicine 26: 115-29

V. Liss PE, Aspevall O, Karlsson D, Forsum U (2001). "Communication in medicine- the importance of conceptual clarification." (Submitted)