Biomedical subjects

G Thue

Publications and source records attributed to G Thue.

At least 19 recordsLinked to original sources

PubMed2001

[Quality of rapid tests for determination of infectious mononucleosis].

BACKGROUND: The Norwegian centre for quality assurance in primary health care, NOKLUS, was established in 1992 to ensure the quality of laboratory analyses performed in primary health care. This article evaluates results from the surveys of infectious mononucleosis. MATERIAL AND METHODS: From 1996 to 2000, five serum panels were sent to participating practices in order to control test-kits designed for serological rapid diagnosis of infectious mononucleosis. 648 practices participated in this external quality assessment in 2000. Target values were determined using the Paul Bunell Davidsohn test. The results obtained for each type of test and variables that might have affected the results were evaluated. RESULTS: Outdated kits or kits close to the date of expiration showed poorer results than the other test-kits. The quality of the results depended mainly on the type of test-kit used and the training level of the persons performing the analyses. INTERPRETATION: The best performing tests in these surveys were Clearview IM (Unipath Limited) and Contrast Mono (Genzyme diagnostics). These two tests are among the three most frequently used tests, out of a total of thirteen, in our surveys.

Agglutination Tests↗

PubMed2001

External quality assessment of general practice laboratories: organizational issues and interpretation of feedback reports.

OBJECTIVE: To describe and evaluate organizational issues and handling of feedback reports in the Norwegian external quality assessment scheme (EQAS) for general practice laboratories. METHODS: Postal questionnaire survey including three EQAS feedback reports (one with acceptable analytical quality, one indicating a problem with precision and one indicating bias of the measurement method) to 535 randomly selected general practices. RESULTS: The response rate was 80%. Two-thirds of practices were group practices, and 16% of practices employed a medical technologist. Nearly all practices found the manual for analysing quality control material easy to understand, and samples seemed to be handled as part of routine laboratory work. Feedback reports were primarily studied by those responsible for laboratory work in the practice, and only in 60% of practices by doctors. Practice routines for follow-up of deviant results in the EQAS seemed to have been established. Internal quality control was performed in 90% of group practices and in 71% of solo practices. Concerning responses to feedback reports, there seemed to be a substantial need for assistance even for less deviant results, although most actions suggested by the practices were adequate. On the other hand, assistance was not always sought for "critical" problems. CONCLUSIONS: EQAS is feasible in primary care, but instructions must be clear and conclusions in the feedback reports made very explicit. Easy-to-reach assistance from medical technologists with expertise in general practice laboratory instruments and routines seems paramount.

Family Practice↗

PubMed2001

Patient-derived quality specifications for instruments used in self-monitoring of blood glucose.

BACKGROUND: Instruments for self-monitoring of glucose (SMBG) are increasingly used by diabetic patients. Information is limited on how patients use and interpret SMBG results, and no quality specifications for such instruments are based on the opinions of patients. METHODS: Type 1 diabetic patients (n = 201) filled in a questionnaire eliciting daily limits for blood glucose (BG) and changes of BG considered significant at different glucose concentrations. From these responses, patient-derived quality specifications were calculated in different clinical situations with low, intermediate, and high BG concentrations. RESULTS: Mean age of the patients was 31.8 years, mean diabetes duration was 14.7 years, and mean SMBG duration was 10.0 years with a mean frequency of 11.2 measurements/week. The threshold for hypoglycemic symptoms was 3.0 mmol/L (54 mg/dL), and the mean daily BG target window was 4.3-10.4 mmol/L (77-187 mg/dL). The mean absolute BG changes producing actions from the patients ranged from 1.1 mmol/L (20 mg/dL) to 3.6 mmol/L (65 mg/dL). The analytical quality specifications for imprecision depended on the clinical situation. Excluding the hypoglycemic situation, the analytical CV needed to fulfill the expectations of 75% of the patients was 6.4-9.7%. The analytical quality specification for CV at hypoglycemic concentrations was 3.1%. CONCLUSIONS: Instruments for self-measurements of glucose with an imprecision (CV) of < or = 5% and bias < or = 5% meet the expectations of >75% of patients in clinical situations other than hypoglycemia.

Adolescent↗

PubMed2001

Interpretation of hemoglobin A(1c) (HbA(1c)) values among diabetic patients: implications for quality specifications for HbA(1c).

BACKGROUND: Few studies have examined patients' views, knowledge, and understanding of glycohemoglobin A(1c) (HbA(1c)) testing. We explored such issues in patients with type 1 diabetes and used their statements to estimate analytical quality specifications for HbA(1c) testing. METHODS: We recruited 201 patients from a hospital outpatient clinic. A questionnaire was used to collect information on diabetes characteristics, perceived knowledge of HbA(1c), last HbA(1c) value, HbA(1c) target value, and thresholds for action. Patients were asked to indicate the magnitude of change in HbA(1c) from 9.4% that they would consider to be a true (real) change; from their responses, we calculated patient-derived quality specifications for HbA(1c). RESULTS: Fifty-eight percent of the patients felt they had "high" knowledge about HbA(1c), and >80% of responders knew their last HbA(1c) value, their target HbA(1c), and the threshold value of HbA(1c) for treatment intensification. The mean acceptable HbA(1c) value was 7.5%. Patients with lower values on their most recent tests reported lower target values for HbA(1c) and lower values for the upper HbA(1c) threshold for treatment intensification. An analytical CV (CV(a)) of 3.1% would be satisfactory for 75% of patients when HbA(1c) is increasing (80% confidence), and a CV(a) of 3.2% would be satisfactory for 75% when HbA(1c) is decreasing (95% confidence). CONCLUSIONS: Type 1 patients' perceived knowledge about HbA(1c) testing is high. They are well informed about their own personal results and about target values and the upper HbA(1c) threshold for action. The patient-derived analytical quality specification for imprecision (CV) is 3.1%.

Adolescent↗

PubMed2000

Use and interpretation of HbA1c testing in general practice. Implications for quality of care.

We evaluate the interpretation and use of HbA1c results in general practice in relation to diabetes follow-up and case-finding. As part of an external quality assurance scheme for laboratory analyses, two case histories were mailed to all Norwegian GPs with equipment for HbA1c analysis in their office laboratory (n=566) and to a random sample of GPs without such instruments (n=419). Patient A represented a monitoring situation and the GPs were asked to state changes in HbA1c signifying any improvement or deterioration of metabolic control. The initial HbA1c value stemmed from analysis of quality control material in the instrument group and was a preset value for the other group. In patient B, we focused on the use of HbA1c and other laboratory tests in diabetes case-finding. In the monitoring situation, 22% of GPs in the instrument group misclassified changes in HbA1c values, since these were less than the analytical uncertainty. Further, when interpreting HbA1c results, 64-93% of GPs (i) assumed that analytical quality was better than it really was, (ii) did not appreciate biological variation of HbA1c, or (iii) acted on small differences to be on the safe side. In case-finding, HbA1c was deemed important by 29% of GPs; doctors choosing not to perform a glucose tolerance test relied more on HbA1c. GPs have to be aware of analytical quality and biological variation when interpreting HbA1c results. The present limitations of HbA1c in the diagnosis of diabetes are not properly understood.

Aged↗

PubMed1999

Quality specifications derived from objective analyses based upon clinical needs.

The well-informed physician should be the best to judge the analytical quality needed for a specific clinical action. By presenting the physicians with well-designed case histories, it is possible to extract the clinical knowledge pertinent to analytical quality. The clinicians are asked which changes in the concentration of an analyte will cause them to change actions concerning the patient. It must be possible to detect these changes with a certain probability and this presupposes a certain analytical quality which can then be calculated. It is important that a strict methodology both for constructing case histories and for calculation of the required analytical quality is used.

Clinical Laboratory Techniques↗

PubMed1998

[Better quality of thrombotest in family practice. Results from the NOKLUS survey 1993-97].

The Norwegian centre for external quality assurance of primary health care laboratories (Norwegian abbreviation: NOKLUS) was established in 1992. In 1997 about 1,800 practices participated in NOKLUS' quality assurance schemes, and 576 of these participated in the PT survey. Participation is voluntary and free of charge. The interlaboratory variation (CV%) was 17.7% in 1993 and 13.3% in 1997, and the percentage of results classified as "poor" has decreased from 7-8% in 1993 to 4% in 1997. These data indicate that participation in the scheme has led to a widespread improvement in laboratory performance. Norwegian primary health care practices now seem to analyse PT just as accurately as the Norwegian hospital laboratories. Logistic regression showed that the two most important factors for ensuring quality analysis were having a medical laboratory technician perform the PT analyses, and using an analyzer rather than a manual procedure.

Family Practice↗

PubMed1996

[Quality of hemoglobin and glucose analysis in general practice. Results from the NOKLUS (Norwegian Health Authority) surveys 1994].

In 1992 the Norwegian health authorities and the Norwegian Medical Association initiated a joint project to secure the quality of laboratory analyses performed in primary health care. Two coordinated activities were established: in each of the 19 Norwegian counties a medical laboratory adviser was engaged, linked to the central clinical chemistry laboratory in that county. These advisers assist general practitioners and primary care specialists in securing the quality of laboratory procedures performed on their own premises. In addition, a Norwegian centre for external quality assurance in primary care (Norwegian abbreviation NOKLUS) was established. In 1994 NOKLUS had about 1,600 participants (comprising 95% of the relevant general and specialist practices). Tolerated limits are based on target intervals combined with a percentage tolerated deviation. Fresh material is used for haemoglobin, and target values are determined by two independent laboratories using the reference method. The article describes the results of the surveys of glucose and haemoglobin tests in 1994.

Blood Glucose↗

PubMed1994

The erythrocyte sedimentation rate in general practice: clinical assessment based on case histories.

Thirteen case histories were mailed to 273 general practitioners to study the clinical assessment of the ESR. Participants were asked to state their reference limits for the ESR, as well as action values for the ESR in several clinical situations typical of primary care. The action value should represent the minimal ESR change from a given value necessary to initiate some kind of action towards the patient. The response rate was 76%. In most case histories, half the general practitioners reacted on an ESR change of 10 mm h-1 or less, which is usually due to analytical and biological variation, thus underlining the need for good analytical quality. In general the response was of the same magnitude irrespective of type of case history, i.e. whether the ESR was used in case finding, in diagnosis, or in follow-up. Estimation of the reference limit displayed considerable variation, and knowledge of a previous 'normal' ESR was of minor clinical importance. Furthermore, we found substantial variation regarding the change in ESR necessary to take action in different clinical situations. In principle, for many general practitioners the action value increased as the given ESR increased whereas others reacted on a constant change in ESR, or the change necessary to take action depended on the clinical situation. We conclude that both the different assessments as to the clinical significance of the ESR, and the unawareness of the significance of analytical and biological variation indicate that guidelines for rational use are needed.

Adult↗

PubMed1994

Survey of office laboratory tests in general practice.

OBJECTIVE: To describe the types of laboratory test done in general practice, and to investigate whether practice characteristics were associated with the implementation of certain tests or instruments. SETTING: A questionnaire was mailed to an 8% random sample of Norwegian GPs. RESULTS: 85% responded; and we obtained data from 175 office laboratories. Medical secretaries did most of the analytical work. The "basic" repertoire consisted of haemoglobin, ESR, glucose; urine test strips, microscopy, culture, and HCG; and faecal occult blood. Group practices had a larger repertoire than had solo practices. Overall, 34% of the practices had urine strips with fields for leucocytes and nitrite, 26% had a cell counter, and 17% did clinical chemistry. A large number of different test methods and instruments were in use, but in most cases one or two brands had a market share of more than 50%. Logistic regression showed that employing a medical laboratory technician was associated with a large analytical repertoire, and the use of cell counters and clinical chemistry analyzers. The GP's form of payment (fixed or fee-for-service) did not influence the repertoire. CONCLUSIONS: The diversity of test methods and instruments makes quality assurance difficult, and recommendations are overdue.

Clinical Laboratory Techniques↗

PubMed1993

Performance of the Reflotron and the Seralyzer in primary health care.

Results from an external quality control of 212 Reflotron and 19 Seralyzer primary care users are presented and compared with performance in 60 hospital laboratories. Respondent deviation was assessed by testing for differences in the distribution of individual deviations from an assigned value for hospital laboratories, or from a general average of the measurement procedure for the Reflotron or the Seralyzer users respectively. Respondent deviation in the Reflotron group matched hospital laboratory deviation, whereas deviation in the Seralyzer group was larger for aspartate aminotransferase, cholesterol and potassium. Seralyzer deviation was larger compared with Reflotron deviation. Imprecision was better in the hospital group than in the Reflotron group for alanine aminotransferase, aspartate aminotransferase, bilirubin, and creatinine whereas Reflotron users performed better than hospitals and Seralyzer users for uric acid; the Seralyzer group was inferior to hospitals for aspartate amino-transferase and potassium. The analytical quality of a subgroup of 138 Reflotron and 18 Seralyzer primary care users was assessed and these users were divided into 'good' and 'other' categories. Good performance was associated independently with use of the Reflotron, with operation by laboratory educated personnel, and with doing comparably few analyses per week. We conclude that the Reflotron is suitable for primary case use whereas the Seralyzer is less suitable.

Blood Chemical Analysis↗

PubMed1993

Dry chemistry instruments in primary care. I. Operating conditions and financial considerations.

The objectives of this study were to describe the operating conditions of dry chemistry instruments in primary care, as well as to elucidate financial aspects in general practice fee-for-service settings. We used questionnaires mailed to all users of the two most used dry chemistry instruments in Norway, as well as to a 14% random sample of Norwegian GPs. The overall response rate was 79%. The mean number of dry chemistry analyses varied considerably between individual users, but in general a substantial number of analyses were carried out. Even though most analyses on the instruments' repertoire were available in all user groups, a total of 13 additional constituents were suggested to be included in the repertoire. In occupational health care most results were ready when the client was present; this was not the case in general practice. The instruments were more profitable when more constituents were analysed per sample, although profitability varied substantially in the period studied (1986-1989). A discrete time history event analysis revealed that net profit earned, lower instrument price, available information about the technology and being in solo practice significantly influenced the decision to buy an instrument in fee-for-service practices.

Blood Chemical Analysis↗

PubMed1993

Dry chemistry instruments in primary care. II. Comparison of users with non-users.

One way of studying the impact of dry chemistry desk-top instruments in primary care is by comparing users and non-users of this technology with respect to practice setting and changes in everyday practice, as well as to elucidate reasons for not implementing this technology. We therefore mailed a similar questionnaire to all users of the most-used dry chemistry instruments in Norway (n = 298) and to a 14% random sample of general practitioners (n = 381), and a 40% random sample of doctors in occupational health care units (n = 181). The response rate was 77-79% and 200 users and 281 non-users could be included. In general practice, more users were solo practitioners and more users had a cell counter in the office laboratory; fewer occupational health care users kept computerized records. Users reported improvement in diagnosis and treatment and claimed that patient satisfaction had improved. In general, an increase in the number of tests was estimated. Non-users were more pessimistic with regard to improvements in office laboratory service, and stated perceived problems regarding cost, workload and analytical quality as well as good service from the hospital laboratory as reasons for not implementing such instruments in their practice.

Attitude of Health Personnel↗

PubMed1993

Clinical goals for measurement of hemoglobin in primary care as assessed by paper vignettes.

A random sample of 10% (273) Norwegian general practitioners (GP) received a questionnaire including 11 case stories. For each case the GP was asked to fill in an action value for hemoglobin which should represent the minimal change considered necessary by that general practitioner to take action towards the patient. These minimal changes could then be used for calculation of imprecision goals assuming that there was no change in the bias of the two measurements. The analytical imprecision goals (CV) derived from the different case stories varied between 0% and 7.8% with a mean of 2.8% accepting a false positive rate of 5%. The GPs assessment of a single case story also varied substantially.

Chemistry, Clinical↗

PubMed1993

Comparison of the use of a dry chemistry analyser in primary care in Norway and the United Kingdom.

The results of a quality assessment survey of the most commonly used dry chemistry instrument in primary care in Norway and the United Kingdom, the Reflotron (Boehringer), are reported including an evaluation of some of the operational characteristics of the Reflotron users. The primary care users in Norway taking part in the study comprised 95 occupational health care departments and 89 general practices. In the UK, primary care users taking part were 95 occupational health care departments and 37 general practices. In terms of both accuracy and precision evaluation of concentrations of bilirubin, cholesterol, gamma-glutamyl transferase, glucose, triglycerides, urea and uric acid by primary care users was similar in the two countries, and to that of 60 Norwegian laboratories. Examination of operational characteristics revealed a lack of effective quality control measures in both countries, and some differences in the pattern of usage between primary care users in Norway and the UK, especially in general practice. The result of Reflotron tests were ready before the patient left in a considerably higher proportion of general practices in the UK than in Norway. It is concluded that the Reflotron is suitable for primary care use, but good, routine quality of analysis must be ensured through collaboration between primary care users and clinical chemists.

Blood Chemical Analysis↗

PubMed1991

[Which laboratory tests should be performed by general practitioners--and how to assure good analytical quality?].

Near patient testing is increasing both in Norway and abroad. Having test results ready when the patient is present is beneficial in a number of clinical situations, as well as being efficient for both doctor and patient. However, the analytical quality in general practice has proved unstable and in many instances poor. Public expenditures to reimburse near patient tests are soaring. Therefore, high priority must be given to ensuring that the practitioner's laboratory is sound, both professionally and economically. The following items are considered important: All analytical work should be subjected to regular quality assessment. We list a number of constituents that are suitable for near patient analysis. The constituents are divided in two groups: those that all practices should be capable of analyzing, and constituents which should be analyzed in practices with doctors with a special interest in this field. We also suggest changes in the Norwegian public system of reimbursement for near patient testing.

Chemistry Techniques, Analytical↗

PubMed1991

Clinical assessment of haemoglobin values by general practitioners related to analytical and biological variation.

Twelve case stories were mailed to 273 general practitioners to study the clinical assessment of haemoglobin values. For each case the general practitioner was asked to fill in the haemoglobin value representing the minimal change from a given value considered necessary to take action. haemoglobin change corresponding to the median haemoglobin value stated was transformed to a so-called 'medically useful coefficient of variation' in order to relate clinical demands to analytical and biological variation. The average medically useful coefficient was calculated to 3.9% (range 2.3-7.8%). We found that general practitioners assess haemoglobin values rather uniformly, although their judgement varies substantially with the clinical situation; they are not fully aware of the consequences of analytical and biological variation, and the advantage of knowing a previous haemoglobin value is not recognized. The analytical imprecision of haemometers based on clinical demands should be 2.8%, and the analytical quality should be the same in primary and secondary care.

Adult↗

PubMed1991

Performance of cell counters in primary health care.

The results are presented from two external quality control surveys of cell counters in primary health care. The precision of haemoglobin measurements in the normal range was better than that obtained by conventional haemometers. The analytical quality of leucocyte analyses was about the same as that performed by hospital instruments. The precision of cell counters with respect to thrombocytes was poorer than that obtained on hospital instruments, especially in the lower level. Celldyn and Sysmex instruments performed best among the instruments examined. Reliable cell counter results were associated with medical laboratory technicians as operators of the instruments. To improve the analytical quality of the laboratory in primary health care, it appears necessary to establish an external quality assurance programme, including a laboratory consultancy service.

Blood Cell Count↗