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Comparison of two different technologies measuring the same analytes in view of the In Vitro Diagnostic Regulation (IVDR)

  • Noel Stierlin EMAIL logo , Andreas Hemmerle , Karin Jung , Jörg Thumfart , Martin Risch and Lorenz Risch ORCID logo
Published/Copyright: August 2, 2024
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Journal of Laboratory Medicine
From the journal Journal of Laboratory Medicine Volume 49 Issue 1

Abstract

Objectives

This study systematically compared the performance and comparability of two medical laboratory analytical instruments, the conventional wet chemistry analyzer (cobas) and the dry slide technology (Vitros), across various clinical chemistry assays.

Methods

The evaluation focused on assessing imprecision, inaccuracy, recovery, and method comparison using leftover patient serum samples.

Results

The results indicated good to very good agreement for most clinical chemistry analytes, with larger differences observed for comparison of serum patient samples on albumin and protein.

Conclusions

Understanding and acknowledging method-specific variations, are crucial for accurate result interpretation in clinical laboratories. This study contributes valuable insights to ongoing discussions on method standardization.

Keywords: method comparison; wet chemistry; dry slide technology; cobas; Vitros; IVDR

Introduction

Different technologies used for measuring analytes in medical laboratories should ensure that the delivered results are comparable. Manufacturers of reagents must ensure adherence to the traceability chain by developing a proper calibrator kit as also required by the In Vitro Diagnostic Regulation (IVDR) [1], [2], [3], [4], [5]. Additionally, laboratories must strictly follow the provided manufacturer’s instructions to align with the traceability concept. As a minimum requirement, calibrators and quality control material should mimic patient materials, a concept known as commutability [6], 7]. Following all these steps should yield comparable results. However, variations may still exist due to differences in measurement principles, matrix effects, and/or the composition of various patient samples [8], [9], [10]. Our evaluation aimed to compare conventional wet chemistry analyzer with dry slide technology [11].

Materials and methods

A Vitros 7,600 system (Quidel-Ortho Clinical Diagnostics, Cologne, Germany) was evaluated, and cobas 6000 systems (Roche, Basle, Switzerland) were used for comparison. Both systems were operated and calibrated according to the manufacturer’s instructions. Table 1A and B lists the analytes we evaluated and method principles with some further details.

Table 1A:

Overview of method details for analytes used for the evaluation study for cobas.

Analyte Unit Method cobas Wavelength, nm Traceability Ref interval Lin
ALB g/L Immun turbitity test 505/570 IRMM, ERM-DA470k/IFCC 28–54 3–108
ALKP U/L p-nitrophenol 480/450 IFCC 35–648 5–1,200
ALT U/L IFCC P-5-P 700/340 IFCC 10–50 5–700
AMYL U/L p-nitrophenol maltopentaosid 700/415 Int. Calib. 0.27–8.2 3–1,500
AST U/L IFCC P-5-P 700/340 IFCC 10–50 5–700
Bca µmol/L Jendrassik–Grof 800/546 Man. Jendrassik–Grof <5 1.5–291
Bub µmol/L Calculated <13.6
Ca mmol/L BAPTA 376/340 SRM 956 c Level 2 1.9–2.7 0.2–5
CHOL mmol/L CHOD PAP 700/415 IDMS <5.2 0.1–20.7
CK U/L IFCC NAC 546/340 IFCC f 26–192 m 39–308 7–2000
CREA µmol/L Jaffe 570/505 IDMS f 44–80 m 62–106 15–2,200
dHDL mmol/L CHOD PAP 700/600 CDC >1.68 0.08–3.88
Fe µmol/L Ferrozine 552/659 SRM937 5.38–34.5 0.9–179
GLU mmol/L Hexokinase 700/340 IDMS 0.3–6.72 0.11–41.6
K mmol/L ISE indirect Grav 3.5–5.1 1.5–10.0 
LAC mmol/L Enzym POD 700/660 Prim. Cal. (Roche) 0.5–2.2 0.2–15.5
LDH U/L Lactate-to-pyruvate (L → P) 700/340 IFCC 120–600 10–1,000
Na mmol/L ISE indirect Grav 136–145 80–180 
PHOS mmol/L Ammonium molybdate 700/340 Prim. Cal. (NERL) 0.81–1.45 0.1–6.46
TBIL µmol/L DPD 600/546 Doumas Bis 24 2.5–650
TP g/L Biuret 700/546 SRM 927 64–83 2.0–120 
TRIG mmol/L Enzym. PAP 700/505 IDMS <1.7 0.1–10
UREA mmol/L Talke 700/340 IDMS 2.76–8.07 0.5–40
URIC µmol/L PAP 700/546 IDMS f 142.8–339.2 m 202.3–416.5 11.9–1,487

  1. aBilirubin conjugated, bbilirubin unconjugated.

Table 1B:

Overview of method details for analytes used for the evaluation study for Vitros.

Analyte Unit Method vitros Wavelength, nm Traceability Ref interval Lin
ALB g/L Bromcresolgreen 630 SRM 927 35–50 10.0–60.0
ALKP U/L p-nitrophenol 400 IFCC 38–126 20–1,500
ALT U/L P-5-P activated 340 IFCC 13–69 6–1,000
AMYL U/L Amylopectin 540 p-nitrophenol maltopentaosid 30–110 30–1,200
AST U/L P-5-P activated, leuco dye 670 IFCC 15–46 3.0–750.0
Bc µmol/L Caffeine + benzoate 400 and 460 HPLC method Lauff et al. 0–5 0–462
Bu µmol/L Caffeine + benzoate 400 and 460 HPLC method Lauff et al. 0–19 0–462
Ca mmol/L Arsenazo III 680 SRM 915 2.10–2.55 0.25–3.49
CHOL mmol/L Enzym. Leuco dye 540 SRM 911 <5.2 1.29–8.40
CK U/L NAC 670 Scand committee on enzymes f 30–135 m 55–170 20–1,600
CREA µmol/L Enzym. Leuco dye 670 SRM 914 f 46–92 m 58–110 13–1,238
dHDL mmol/L Enzym. Leuco dye 670 SRM 911 1,03–1,55 0.13–2.84
Fe µmol/L dye 600 SRM 937 f 6.6–30.4 m 8.8–32.4 1.81–107.46
GLU mmol/L GOD POD 540 SRM 917 4.1–5.9 1.11–34.69
K mmol/L ISE, dircet SRM 918 3.5–5.1 serum 1.00–14.00
LAC mmol/L Enzym POD 540 Gravimetrically prepared standard 0.7–2.1 0.50–12.00
LDH U/L Pyruvte ê Lactate 340 Pyruvate-to-lactate (P→L) (buhl) 313–618 100–2,150
Na mmol/L ISE, dircet SRM 919 137–145 75.0–250.0
PHOS mmol/L Ammonium molybdate 670 SRM 200 0.81–1.45 0.16–4.20
TBIL µmol/L Diazo 540 and 460 SRM 916 3–22 1.7–461.7
TP g/L Biuret 540 SRM 927 63–82 20.0–110.0
TRIG mmol/L Enzym leuco dye 540 SRM 1951 <1.69 0.11–5.93
UREA mmol/L Ammonia indicator 670 SRM 912 f 2.5–6.1 m 3.2–7.1 0.71–42.83
URIC µmol/L Enzym leuco dye 670 SRM 913 f 149–369 m 208–506 29.7–1,011.2

For testing the imprecision within a run on the Vitros system, a patient pool serum was used and measured 20 times in a single run for each analyte. Testing the imprecision from day to day over 20 days, we used commercially available quality control materials as recommended by the system manufacturers. For the cobas system, we used Precinorm (lot no. 494700) and Precipath (lot no. 494701), both from Roche. For the Vitros system, both Performance Verifier level I (lot no. J9587) and level II (lot no. K9589) were used from Ortho. Due to the instructions for use we had to proceed with different QC materials. QUALAB is the Swiss QC regulation which laboratories in Switzerland have to follow [12].

For the comparison, we evaluated 48–77 serum patient samples [13] after being tested for the requested analytes in our routine lab on the cobas system. The patients gave written consent to use the so-called leftover samples before the evaluation.

The mean, standard deviation, and coefficient of variation were calculated using an Excel program. For the statistical analysis of the method comparison, we used the Passing-Bablok program (MedCalc Statistical Software, Version 20.027), and the bias plot was done according to Bland-Altman.

Results

For Vitros the coefficient of variation within run for 20 measurements ranged from 0.38 % (triglycerides) to 4.91 % (total bilirubin) (Table 2). The coefficient of variation from day to day over 20 days on the Vitros system was found to be between 0.58 % (phosphate) and 5.90 % (iron) for the low-level quality control material and, for the second level of quality control material, between 0.79 % (sodium) and 6.77 % (conjugated bilirubin) (Table 3). For the cobas system, we observed a range of 0.21 % (unconjugated bilirubin) to 6.62 % (creatinine) for the low-level quality control material and, for the second level, between 0.51 % (potassium) and 6.39 % (creatinine) (Table 3).

Table 2:

Coefficient of variation within run for Vitros (n=20).

Vitros
Analyte Unit Mean CV, % QUALABa, %
ALB g/L 44.60 0.74 12
ALKP U/L 65.90 1.43 18
ALT U/L 23.60 2.08 18
AMYL U/L 70.90 4.52 18
AST U/L 27.90 1.08 18
Bu µmol/L 3.24 2.05 18
Ca mmol/L 2.36 0.62 9
CHOL mmol/L 5.71 0.53 10
CK U/L 82.40 0.81 18
CREA µmol/L 77.01 0.75 18
dHDL mmol/L 1.38 1.27 21
Fe µmol/L 16.73 2.19 20
GLU mmol/L 5.24 0.93 9
K mmol/L 4.38 0.91 6
LAC mmol/L 3.64 0.59 18
LDH U/L 152.60 1.32 18
Na mmol/L 140.20 0.43 6
PHOS mmol/L 1.29 0.63 15
TBIL µmol/L 4.72 4.91 18
TP g/L 72.49 0.67 12
TRIG mmol/L 1.68 0.38 18
UREA mmol/L 5.26 1.91 15
URIC µmol/L 295.71 0.56 12

  1. aPermitted deviations according to QUALAB.

Table 3:

Performance data of variation between days for both cobas and Vitros.

Precinorm cobas PV1 Vitros
Analyte Unit Mean Target value CV, % QUALABa, % Recovery, % Mean Target value CV, % Recovery, %
ALB g/L 23.40 24.40 0.36 12 96 24.70 24.30 2.47 102
ALP U/L 27.00 29.20 1.75 18 92 108.00 110.00 1.24 98
ALT U/L 23.60 24.70 0.70 18 96 21.10 22.00 5.39 96
AMYL U/L 43.00 42.60 1.55 18 101 75.70 80.00 2.53 95
AST U/L 42.80 42.30 1.03 18 101 35.10 35.00 1.58 100
Bc µmol/L 5.70 5.93 2.34 18 96 8.83 8.90 4.19 99
Bu µmol/L 8.25 8.76 0.21 18 94 8.45 8.60 5.69 98
Ca mmol/L 1.48 1.51 1.29 9 98 2.10 2.13 1.66 99
CHOL mmol/L 2.72 2.75 3.33 10 99 3.72 3.80 2.42 98
CK U/L 71.60 78.50 1.77 18 91 156.90 154.00 3.01 102
CREA µmol/L 65.20 65.40 6.62 18 100 80.30 81.30 3.38 99
dHDL mmol/L 0.50 0.52 2.07 21 96 1.25 1.20 3.56 104
Fe µmol/L 13.50 13.70 1.98 20 99 14.50 14.60 5.90 99
GLU mmol/L 3.38 3.40 1.25 9 99 4.68 4.70 2.69 100
K mmol/L 2.55 2.52 0.81 6 101 2.99 3.04 0.92 98
LAC mmol/L 1.46 1.47 3.54 18 99 1.34 1.35 2.39 99
LDH U/L 123.40 120.00 0.95 18 103 181.00 181.00 1.23 100
Na mmol/L 116.70 118.00 0.71 6 99 122.10 122.40 1.40 100
PHOS mmol/L 0.58 0.59 1.18 15 98 1.17 1.15 0.58 102
TBIL µmol/L 8.26 8.76 3.29 18 94 26.30 26.70 4.56 99
TP g/L 40.00 41.50 0.69 12 96 37.80 38.60 2.14 98
TRIG mmol/L 1.14 1.13 0.72 18 101 1.34 1.40 3.85 96
UREA mmol/L 5.23 5.21 2.39 15 100 6.88 6.70 2.52 103
URIC µmol/L 197.60 199.00 1.72 12 99 232.10 233.80 1.10 99
Precipath cobas PV 2 Vitros
Analyte Unit Mean Target value CV, % QUALABa, % Recovery, % Mean Target value CV, % Recovery, %
ALB g/L 31.50 32.90 2.09 12 96 44.70 44.81 1.90 100
ALP U/L 142.56 142.00 1.68 18 100 466.00 464.00 1.10 100
ALT U/L 78.80 80.20 0.80 18 98 145.80 155.00 3.47 94
AMYL U/L 129.20 129.00 0.61 18 100 307.80 317.00 3.54 97
AST U/L 108.30 106.00 0.76 18 102 169.80 176.00 2.22 96
Bc µmol/L 27.53 28.50 0.79 18 97 65.60 67.50 6.77 97
Bu µmol/L 32.28 35.30 0.67 18 94 32.45 32.80 5.69 98
Ca mmol/L 2.58 2.64 2.89 9 98 2.92 2.96 1.20 99
CHOL mmol/L 4.50 4.61 3.33 10 98 6.53 6.70 1.89 97
CK U/L 236.40 253.00 2.15 18 93 787.50 819.00 2.84 96
CREA µmol/L 165.00 161.00 6.39 18 102 443.90 462.30 1.18 96
Fe µmol/L 27.50 27.60 0.94 20 100 35.80 38.00 2.82 94
GLU mmol/L 6.44 6.49 1.09 9 99 16.38 16.70 1.42 98
dHDL mmol/L 0.77 0.81 2.87 21 95 1.62 1.60 4.79 101
K mmol/L 4.14 4.12 0.51 6 100 5.39 5.50 0.97 98
LAC mmol/L 3.42 3.52 1.23 18 97 3.61 3.68 3.01 98
LDH U/L 181.30 181.00 0.74 18 100 565.60 572.00 2.12 99
Na mmol/L 140.00 141.00 0.58 6 99 143.40 144.50 0.79 99
PHOS mmol/L 1.31 1.30 1.31 15 101 2.35 2.39 2.78 98
TBIL µmol/L 44.60 45.80 1.97 18 97 254.90 253.80 3.44 100
TP g/L 53.20 54.90 1.31 12 97 69.00 69.80 3.20 99
TRIG mmol/L 1.46 1.49 0.91 18 98 2.88 2.90 1.46 99
UREA mmol/L 13.50 13.70 1.35 15 99 19.60 19.80 2.06 99
URIC µmol/L 332.40 339.00 1.20 12 98 664.10 654.30 2.30 101

  1. aPermitted deviations according to QUALAB.

Regarding recovery, when comparing the calculated mean with the target value of the representative quality control material, we found values for the Vitros system for clinical chemistry analytes between 94 % (ALT, iron) and 104 % (dHDL). For the cobas system, the values ranged between 91 % (CK) and 103 % (LDH) (Table 3). All calculated performance data on imprecision and inaccuracy are below the QUALAB requirements and therefore passing our expectations.

Comparing different patient serum samples with the two systems delivered a coefficient of correlation between 0.832 (albumin) and 0.996 (glucose and uric acid), while slopes ranged from 0.760 (amylase) to 1.083 (urea) (Table 4). The graphical presentation of the comparison of albumin, total protein, and sodium has been chosen for discussion (Supplementary Figure 1A–F).

Table 4:

Results of statistical analysis of method comparisons between cobas and Vitros.

Analyte Unit n Mean cobas Mean Vitros Diff Median cobas Median vitros Diff Slope CIa CI Intercept CI CI r CI CI Low High
ALB g/L 72 39.8 44.2 1.11 40.1 45 1.12 0.786 0.672 0.899 13.1 8.8 17.7 0.832 0.743 0.892 26.5 48.9
ALP U/L 59 97.9 85.0 0.87 71 60 0.85 0.872 0.833 0.944 1.3 3.4 4.2 0.958 0.931 0.975 40 499
ALT U/L 59 19.5 20.5 1.05 15 17 1.13 0.955 0.889 1.000 1.5 1 2.8 0.911 0.855 0.947 8 55
AMYL U/L 59 66.4 68.9 1.04 64 66 1.03 0.760 0.690 0.833 19.0 13.5 22.8 0.963 0.938 0.978 22 123
AST U/L 59 32.1 28.5 0.89 22.00 28.00 1.27 1.000 0.929 1.100 5.0 3.4 6.6 0.918 0.865 0.950 14 56
Bu µmol/L 42 7.1 5.8 0.82 6.05 5.0 0.83 1.044 0.971 1.127 1.13 −1.44 −1.90 0.958 0.923 0.978 2.5 25.7
Ca mmol/L 63 2.42 2.40 0.99 2.4 2.37 0.99 1.016 1.000 1.058 −0.050 −0.149 −0.010 0.918 0.867 0.950 1.64 3.48
CHOL mmol/L 50 4.73 4.97 1.05 4.45 4.70 1.06 1.000 1.000 1.060 0.20 −0.01 0.20 0.995 0.991 0.997 2.9 7.8
CK U/L 59 100.03 92.19 0.92 84 79 0.94 0.857 0.833 0.878 6.6 4.9 8.3 0.993 0.988 0.996 17 349
CREA µmol/L 59 75.20 72.88 0.97 72 69 0.96 1.000 0.920 1.080 −2.0 −7.3 4.1 0.966 0.944 0.980 46 169
dHDL mmol/L 50 1.51 1.50 0.99 1.50 1.50 1.00 1.024 1.000 1.063 −0.050 −0.110 −0.010 0.988 0.979 0.009 0.65 2.47
Fe µmol/L 50 17.26 18.13 1.05 17.30 17.65 1.02 1.035 1.000 1.070 0.41 −0.20 0.80 0.991 0.983 0.995 7.2 35.9
GLU mmol/L 50 5.06 5.02 0.99 4.80 4.80 1.00 1.000 1.000 1.099 0.0 −0.2 0.0 0.996 0.994 0.998 1.8 14.2
K mmol/L 57 4.96 4.98 1.00 4.30 4.40 1.02 1.000 1.000 1.000 0.1 0.1 0.1 0.988 0.980 0.993 3.5 8.5
LAC mmol/L 60 2.00 1.90 0.95 2.44 2.35 0.96 1.042 1.000 1.071 −0.18 −0.26 −0.10 0.993 0.989 0.996 0.8 7.2
LDH U/L 59 164.73 160.76 0.98 163 161 0.99 0.900 0.837 0.977 12.5 −1.1 22.4 0.923 0.874 0.954 75 247
Na mmol/L 77 137.08 138.26 1.01 138 140 1.01 1.000 0.800 1.000 1.0 1.0 29.2 0.865 0.795 0.912 113 170
PHOS mmol/L 50 1.28 1.34 1.05 1.26 1.29 1.02 0.962 0.923 1.000 0.110 0.060 0.160 0.983 0.969 0.990 0.57 1.99
TBIL µmol/L 48 6.89 9.91 1.44 5.90 9.15 1.55 1.021 0.952 1.114 3.0 2.3 3.5 0.953 0.917 0.973 2.5 25.7
TP g/L 59 70.34 72.98 1.04 71 72 1.01 1.200 1.000 1.333 −11.6 −20.7 2.0 0.939 0.899 0.964 45 77
TRIG mmol/L 63 1.86 1.90 1.02 1.26 1.34 1.06 1.047 1.032 1.065 −0.030 −0.050 −0.010 0.998 0.997 0.999 0.41 6.33
UREA mmol/L 50 4.70 4.89 1.04 4.43 4.67 1.05 1.083 1.027 1.151 −0.20 −0.50 0.06 0.987 0.978 0.993 2.37 7.69
URIC µmol/L 59 282.54 286.39 1.01 269 270 1.00 1.000 0.983 1.010 4.0 0.6 8.6 0.996 0.993 0.997 153 495

  1. aCI, confidence interval.

Discussion and conclusions

Comparing two different technologies (here, dry chemistry versus conventional wet chemistry) is always challenging for the medical laboratory. Very often, evaluation is done using the same technology and a newer analyzer from the same manufacturer [14], 15]. In those cases, only a slight difference may be observed. Our approach differed as we have two different technologies and manufacturers.

It would be desirable if the methods were referenced to a reference standard material or higher-order method. This is a requirement of the IVDR [1] and is mainly adhered to, at least in methods in clinical chemistry.

As given in Table 1, one may find that for the same analyte, the same traceability philosophy was only sometimes followed. While on the dry slide technology, the reference towards traceability was mainly given by Standard Reference Materials from NIST, the wet technology used different references.

There was predominantly good to excellent agreement for selected analytes in our evaluation. More significant differences were observed only for albumin (Supplementary Figure 1A and B) and total protein (Supplementary Figure 1C and D), while the means in both cases aligned well. Since the methods for measurement of albumin differs (cobas: immun turbidity test; Vitros: bromocresol green) and, also the way of traceability is different (cobas: IRMM, ERM-DA470k/IFCC [16]; Vitros: SRM 927 [17]). This difference has also been described in the literature [18]. Therefore, the found difference was expected. The literature also mentions that standardization using a higher-order calibrator for both methods does not contribute to significant improvement [9], 19].

Another well-known and published challenge in method comparison is sodium [20] (Supplementary Figure 1E and F). Due to the narrow range of the sodium concentration in the body, it is impossible to find samples covering the complete linear range. Therefore, the statistical analysis is limited to the narrow range.

A further aspect of a method comparison with methods traceable to a standard or method of higher order is how close they are. Incorporating insights from studies on Sigma metrics enhances our understanding of assay quality across diverse clinical laboratory settings [21]. Despite inherent challenges in method comparison, such as differing traceability sources and measurement principles, our study underscores the importance of aligning with regulatory standards to ensure accurate and reliable diagnostic testing, as mandated by the IVDR [1].

Our study recognized that the different technologies mainly use different traceability sources. The same reference material was used for iron (SRM 937) and total protein (SRM 927). While for iron, a very close relationship, was overserved in total protein, we detected a bias of about 20 % using the Passing-Bablok method for statistical analysis. The mean values differ by only 5 % (iron), as seen on the bias plots (Supplementary Figure 1B, D, F). The reason for the difference could be explained by using only samples mainly within or close to the reference interval (between 50 and 77 g/L). Here, the statistical analysis is a challenge.

The limit of our study was the use of out-patient material only. Those samples usually show values of the analytes within the reference interval. It is challenging for the lab to get samples from highly diseased patients. Nevertheless, this is the daily focus of our laboratory in measuring those samples, which was also the reason for running the study under real clinical conditions. In conclusion the QUALAB requirements [12] were met. Our study delivered comparable results from evaluation between different technologies. Those studies are rare and therefore the results are remarkable as different concepts of traceability had been given by the respective manufacturers. The evaluation fulfilled our requirements.

Corresponding author: Noel Stierlin, Private University in the Principality of Liechtenstein, Triesen, Liechtenstein; and Dr. Risch Medical Laboratory, Lagerstr. 30, 9470, Buchs, Switzerland, E-mail:

Acknowledgments

We extend our sincerest gratitude to all individuals who contributed to the realization of this study. We would like to express our appreciation to the staff and technicians at Dr. Risch for their invaluable assistance in conducting the experiments and collecting the data. We also acknowledge the patients who generously provided consent for the use of their samples, without whom this research would not have been possible. Their participation is deeply appreciated and underscores the importance of collaborative efforts in advancing medical science. This work is a testament to the collective efforts of many individuals, and we are sincerely thankful for their contributions.

  1. Research ethics: Not applicable.

  2. Informed consent: Not applicable.

  3. Author contributions: NS/LR/MR/HR/AH/KJ/JT conceptualization, NS writing original draft preparation, NS/LR/JT writing reviewing and editing. All authors have accepted responsibility for the entire content of this manuscript and approved its submission.

  4. Competing interests: The authors state no conflict of interest.

  5. Research funding: None declared.

  6. Data availability: Not applicable.

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Supplementary Material

This article contains supplementary material (https://doi.org/10.1515/labmed-2024-0052).

Received: 2024-04-02
Accepted: 2024-07-05
Published Online: 2024-08-02
Published in Print: 2025-02-25

© 2024 the author(s), published by De Gruyter, Berlin/Boston

This work is licensed under the Creative Commons Attribution 4.0 International License.

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https://doi.org/10.1515/labmed-2024-0052
Keywords for this article
method comparison; wet chemistry; dry slide technology; cobas; Vitros; IVDR
Creative Commons
BY 4.0

Articles in the same Issue

  1. Frontmatter
  2. Editorial
  3. “Images from the Medical Laboratory” – editorial remarks
  4. Review
  5. Advances and challenges in platelet counting: evolving from traditional microscopy to modern flow cytometry
  6. Original Articles
  7. Comparison of two different technologies measuring the same analytes in view of the In Vitro Diagnostic Regulation (IVDR)
  8. Assessing the stability of uncentrifuged serum and plasma analytes at various post-collection intervals
  9. Evaluation of different needle gauge blood collection sets (23G/25G) in aged patients
  10. The trend of Epstein-Barr virus DNA loads and CD8+ T lymphocyte numbers can predict the prognosis of pediatric liver transplant recipients with PTLD
  11. Preoperative serum glutathione reductase activity and alpha-fetoprotein level are associated with early postoperative recurrence of hepatocellular carcinoma
  12. Short Communication
  13. Comparison between detection power of MBT STAR-Carba test and KBM CIM Tris II for carbapenemase-producing bacteria
  14. Images from the Medical Laboratory
  15. Clarithromycin crystalluria
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