Measurement Uncertainty Impacts Diagnosis of Diabetes Mellitus: Reliable Minimal Difference of Plasma Glucose Results

Alexithymia, intolerance to uncertainty and mental health difficulties in adolescents with Type 1 diabetes mellitus

BACKGROUND

Type 1 Diabetes Mellitus (T1DM) represents a serious chronic condition affecting a wide number of people. Discussion of the physical issues associated with T1DM pervades the literature, however, there is less discussion of the psychological consequences. Mental health difficulties, alexithymia and uncertainty are present in this population, and known to be harmful for the onset, maintenance and worsening of T1DM. This study aimed to evaluate the presence of these phenomena in people with T1DM.

METHODS

105 participants aged between 11 and 17 years old (M: 13.88; SD: 2.16) affected by T1DM were included in the sample. To assess the presence of mental health difficulties, SAFA scales (Depression, Anxiety and Somatic symptoms) were included in the protocol together with TAS-20 and IUS-12, which evaluate the presence and role of alexithymia and intolerance to uncertainty in the sample, respectively.

RESULTS

A concerning presence of anxiety, depression and somatic symptoms was found in the sample. Mental health difficulties appeared to be consistently present in the sample, often overcoming pathological thesholds. Alexithymia and uncertainty were also common, highlighting their role in T1DM.

CONCLUSIONS

Active mental health difficulties together with high rates of alexithymia and intolerance to uncertainty were prevalent in the sample of adolescents with diabetes.

Impact of diabetic peripheral neuropathy on gait abnormalities in patients with type 2 diabetes mellitus

Background

Many patients with type 2 diabetes (T2DM) suffer from diabetic peripheral neuropathy (DPN) and impaired muscle coordination. These changes may lead to walking instability, and gait abnormalities resulting in increased fall risk and lower limb amputations. The aim of this study was to assess the impact of DPN and patient footwear on the gait in patients with diabetes, in addition to Comparing the peak plantar pressure (PPP) in patients with and without DPN and assessing its association with gait abnormalities.

Methodology

This is an observational case-control study. Forty Subjects with T2DM were divided into two age and sex-matched groups, 20 subjects each. Group A: subjects with DPN. Group B: subjects without DPN. All study participants were subjected to a thorough history taking, clinical examinations focusing on detailed foot examination, PPP assessment, and functional gait evaluation.

Results

The results obtained in this study showed a median gait assessment score of 21 (17.0-22.5) for group A and 26 (23.5-26.0) for group B which was statistically significant (p < 0.001). There was no statistically significant difference between both groups (p > 0.05) regarding the assessment of footwear appropriateness. Comparing the PPP measurement among both studied groups, the prevalence of an elevated PPP was 80% in group A compared to 65% in group B, which was statistically non-significant, p = 0.288.

Conclusions

Gait abnormalities are common among patients with T2DM even in the absence of DPN. However, the presence of DPN was the strongest independent risk factor for gait abnormalities among the studied factors.

Evaluation of a pneumatic tube system carrier prototype with fixing mechanism allowing for automated unloading

OBJECTIVES

A carrier prototype by Aerocom^® (Schwäbisch Gmünd, Germany) for pneumatic tube systems (PTS) is able to transport 9 blood tubes which are automatically fixed by closing the lid. In this study, we examined the influence of the transport on blood sample quality using the carrier prototype comparing to courier transport and a conventional carrier (AD160, Aerocom^®).

METHODS

Triplicate blood samples sets (1 lithium heparin, 1 EDTA, 1 sodium citrate) of 35 probands were split among the transportation methods: 1. courier, 2. conventional carrier, and 3. carrier prototype. After transport 51 measurands from clinical chemistry, hematology and coagulation were measured and compared.

RESULTS

Overall, 49 of the investigated 51 measurands showed a good concordance among the three transport types, especially between the conventional carrier and the carrier prototype. Focusing on well-known hemolysis sensitive measurands, potassium showed no statistically significant differences. However, between courier and both carrier types lactate dehydrogenase (LDH) and free hemoglobin (fHb) showed statistically significant shifts, whereas the clinical impact of the identified differences was neglectable. The median concentration of fHb, for example, was 0.29 g/L (18 µmol/L), 0.31 g/L (19 µmol/L) and 0.32 g/L (20 µmol/L) for courier transport, conventional carrier and carrier prototype, respectively. These differences cannot be resolved analytically since the minimal difference (MD) for fHb is 0.052 g/L (3.23 µmol/L), at this concentration.

CONCLUSIONS

The carrier prototype by Aerocom^® is suitable for transportation of diagnostic blood samples. The overall workflow is improved by decreasing hands-on-time on the ward and laboratory while minimizing the risk of incorrectly packed carriers.

Disregarded Measurement Uncertainty Contributions and Their Magnitude in Measuring Plasma Glucose

BACKGROUND

Each measurement is subject to measurement uncertainty (MU). Consequently, each measurement of plasma glucose concentration used for diagnosis and monitoring of diabetes mellitus (DM) is affected. Although concepts and methods of MU are well established in many fields of science and technology, they are presently only incompletely implemented by medical laboratories, neglecting MU of target values of internal quality control (IQC) materials.

METHODS

An empirical and practical approach for the estimation of MU based on the analysis of routine IQC using control samples with assigned target values is presented. Its feasibility is demonstrated exemplarily by analyzing IQC data from one year obtained for glucose employing the hexokinase method with IQC of two different concentrations.

RESULTS

Combined relative extended (k = 2) MU comprising bias, coefficient of variation (CV), and MU of the target values assigned to control materials were about 9% with a lower (~ 56 mg/dL; ~3.1 mmol/L) and 8% with a higher (~ 346 mg/dL; ~19.2 mmol/L) concentration sample, analyzing IQC of one year from three different devices.

CONCLUSIONS

Estimation of MU in this study is quite reliable due to the large number of IQC data from one year. The MU of the target values of the commercial control material in this study was considerably larger than other MU contributions, ie, standard deviation and bias. In the future, the contribution of MU of commercial IQC should be addressed more carefully and technologies to measure glucose should be geared toward smaller MU possible, as needed, especially for glucose concentration measurements in diagnosis and management of DM.

The extended internal QC (eIQC): a new practical approach for quality assurance in point-of-care glucose testing using the POCTopus Software – a pilot study

Background

Quality assurance (QA) in point-of-care testing (POCT) is an important issue for organizing POCT structures within the healthcare sector. In Germany, only one device needs to participate in an external QA program, if the responsible core laboratory is supervising internal quality controls of all other identical POCT devices. This flexible definition of quality control (QC) testing is in line with the fundamentals of ISO 22870 and the ISO 15189, but can only be regarded as a minimum requirement.

Methods

We present a pilot study for an inexpensive new approach for additional POCT QC measurement similar to the external QA program within the medical laboratory using capillary glucose measurement as an example. This new system, referred to as “extended internal QC (eIQC)”, uses in-house generated QC material from leftover full blood from routine diagnostics. We provide information on calculation of target values and acceptance ranges and preliminary data on stability and comparison between POCT and core laboratory testing (COBAS 8000). Additionally, we simulated the approach using three devices within the laboratory as surrogate for three POCT sites. In this pilot study, measurements of QC material beyond the mandatory QA plan are structured and optimized through the use of the POCTopus Software solution.

Results

QC material was easily generated including specification of target values. The software aided in automatized processing of the samples. The software showed limitations in evaluation and monitoring without relevant use of resources. We found a significant bias between measurements on POCT and COBAS 8000 instruments.

Conclusions

The presented new approach for additional QAs for POCT enables POCT coordinators to establish an additional safety and QC level. Further software improvements are required. Further studies are needed for validation and comparison measurements between methods. Overall, this approach offers great potential for POCT structures seeking higher quality standards.

Using ISO/TS 20914:2019 to calculate the measurement uncertainty of immunosuppressive drugs in a clinical laboratory

According to the standard ISO 15189 clinical routine laboratories shall estimate measurement uncertainty (MU) of patient results of their provided measurands. Up to now there was no accepted description on how to perform. Recently, the ISO technical standard ISO/TS 20914 was published giving a practical guide for uncertainty estimation. The immunosuppressive drugs Everolimus, Ciclosporin, Sirolimus and Tacrolimus have narrow therapeutic windows. Hence, their MU should be considered for deducing clinical decisions. Here, a pathway is presented in detail on how to estimate MU measuring immunosuppressants using a widespread CE certified assay via LC-MS/MS technology. Namely, the expanded measurement uncertainties are from 13% to 27% depending on analyte and concentration. The calculation based on n > 2000 measurements each of four control levels within one year. Lower uncertainties were observed if the material was native pooled blood (13% to 17%, n > 300 measurements, one year).