Performance Evaluation of Samsung LABGEO^HC10 Hematology Analyzer

The LABGEO^HC10 weighs 13.5 kg, with dimensions of 344 mm (width) × 293 mm (depth) × 390 mm (height). The analyzer features a graphic color LCD module with a touch screen and built-in thermal printer module. Its internal memory is capable of storing 1000 records with full histograms and individual patient data. The analyzer can be connected to a host computer through a USB port and allows stored records to be archived or restored. The operation of the analyzer requires minimal training of laboratory personnel.

The analyzer is capable of determining 18 parameters including 3-part differential; white blood cell count (WBC), hemoglobin concentration (Hb), red blood cell count (RBC), mean corpuscular volume (MCV), mean corpuscular hemoglobin (MCH), mean corpuscular hemoglobin concentration (MCHC), hematocrit (HCT), RBC distribution width (RDW), platelet count (PLT), mean platelet volume (MPV), plateletcrit, platelet distribution width (PDW), granulocyte percentage, lymphocyte percentage, monocyte percentage (MON%), granulocyte count, lymphocyte count, and monocyte count (MON#).

The LABGEO^HC10 and LH780 were calibrated according to the manufacturers' recommendations before the study started. Manufacturers' quality control material was run on both instruments on a daily basis during the entire study period.

Blood samples drawn from 244 patients and 26 healthy adults with informed consent were used for this study. Residual K₂EDTA-anticoagulated blood samples were taken from the hematology laboratory of Ajou University Hospital, Suwon, Republic of Korea, after routine testing was complete. The leftover specimens were used for precision, linearity, stability, and method comparison. K₂EDTA- and K₃EDTA-anticoagulated blood samples were taken from participants with their prior agreement, and were used for evaluation of the difference by EDTA tube (K₂/K₃) usage. We used K₂EDTA plastic tubes (Becton Dickinson, Franklin Lakes, New Jersey) and K₃EDTA plastic tubes (Greiner Bio-One, Monroe, North Carolina) as containers. All specimens were stored at room temperature and were tested within 6 hours, except in the case of sample stability testing. This study was performed under the approval of the Ajou University Hospital Institutional Review Board.

Within-run imprecision was established according to the H26-A2 guideline.⁷  Twelve samples of various range were assessed by analyzing them 31 times consecutively by LABGEO^HC10.

Repeatability and device/method precision of LABGEO^HC10 was also established according to the EP5-A2 guideline.⁴  Three levels of commercial quality control material (DiatroCont 3 Hematology Control, Clinical Diagnostic Solutions Inc, Plantation, Florida) were run in pairs, 2 times per day (with at least 5-hour intervals) for 25 operating days.

Linearity for WBC, Hb, RBC, and PLT was evaluated according to the EP6-A guideline.⁵  Briefly, we prepared 5 levels of analytes by mixing, diluting, or concentrating blood samples. The prepared samples were tested 4 times each and the linearity was obtained by polynomial regression analysis for first-, second- and third-order polynomials.

The LABGEO^HC10 was compared with the LH780 for the following parameters: WBC; the numbers and percentages of granulocytes, lymphocytes, and monocytes; RBC; Hb; HCT; MCV; MCH; MCHC; RDW; PLT; and MPV according to the EP9-A2.⁶  Briefly, each sample was measured in duplicates with both units, and the data of 40 samples were selected to cover clinically relevant ranges for each parameter. Another 24 samples with PLT less than 50 × 10³/μL were used for an additional evaluation of low PLT.

Carryover for WBC, Hb, RBC, and PLT was assessed by following the recommendation of the International Council for Standardization in Haematology⁸  and the H26-A2 guideline.⁷  Briefly, 3 consecutive analyses of a patient sample with high analyte concentration (H1, H2, and H3) were followed by 3 consecutive analyses of a patient sample with low analyte concentration (L1, L2, and L3). Carryover (%) was calculated from the formula: 100 × (L1–L3)/(H3–L3). This process was repeated 9 times and 95%, 97.5%, and 99% confidence intervals were calculated.

Samples from 10 healthy adults were used for the evaluation of sample stability. Two sets of samples, which were drawn at the same time, were analyzed 10 times at 0, 6, 12, and 24 hours after blood collection, with 1 set stored at room temperature (RT) and the other at 4°C.

We collected blood into 2 different EDTA tubes (K₂EDTA and K₃EDTA) from 50 patients and analyzed them to evaluate the difference of the results.

Data analysis was carried out by using Microsoft Excel 2007 (Microsoft, Redmond, Washington) and SPSS v11.0 (SPSS Inc, Chicago, Illinois). We performed polynomial regression analysis for first-, second-, and third-order polynomials for linearity access.⁵  The effect of EDTA tube (K₂ versus K₃) was analyzed by paired t test and the sample stability by 1-way analysis of variance test. For the method comparison and bias estimation, we computed 95% confidence interval of predicted bias and compared it to internal performance criteria.⁶ 

Within-run precision for normal and abnormal patient sample results is shown in Table 1; results are shown to satisfy the manufacturer's specification for all of the measured parameters. Repeatability and device/method precision is shown in Table 2; results are shown to satisfy the manufacturer's specification for all of the measured parameters, except for low PLT. No technologic problems with the instrument occurred during the evaluation period of 8 weeks.

Linearity analysis for WBC, Hb, RBC, and PLT is shown in Table 3; it showed nonsignificance for all nonlinear coefficients for all 4 parameters measured.

Results for the method comparison of the LABGEO^HC10 with the LH780 are presented in the Figure. All parameters showed r values >0.95 with the exception of MON# (r = 0.9309), MCHC (r = 0.3778), and MPV (r = 0.9259). Results for the bias estimation of the LABGEO^HC10 with the LH780 are presented in Table 4.

Minimal carryover (<1%) was observed for all the parameters investigated (Table 3).

All parameters, except for the percentage and count of monocytes, showed 24-hour long-term stability for normal samples both at RT and at 4°C. The MON% and MON# showed statistically significant differences even after only 6 hours at 4°C, but were stable up to 6 hours and 12 hours, respectively, at RT.

All parameters except Hb, RBC, and HCT showed no statistically significant differences by the type of EDTA tubes used. The difference of the 3 red cell parameters was minimal (<1%) and the correlation between the different tubes was excellent for Hb (r = 0.997), RBC (r = 0.992), and HCT (r = 0.993).

Despite the application of previously proven technology to a commercial product, instruments of such critical importance as hematology analyzers should be validated technically before implementation in daily practice. The automated LABGEO^HC10 Hematology Analyzer is easy to use and requires minimal training for operation. This study showed that the analyzer provides reliable and comparable results to instruments that are currently used in clinical laboratories.^9–12 

Overall results of the repeatability and device/method precision satisfied the manufacturer's specifications, except for low PLT. The coefficient of variation at low PLT was slightly higher than the coefficient of variation claimed by the manufacturer, though it was still acceptable according to EP5-A2 specifications.⁴  The imprecision of automated platelet counts in the thrombocytopenic range is a well-documented problem.^11,13–15  The LABGEO^HC10 showed an overall good correlation with the LH780, except for MCHC. The poor correlation of MCHC has also been previously reported in the literature.^9,11,12,16 

We determined if the LABGEO^HC10 is a suitable replacement for the LH780, even though the 2 analyzers are very different in terms of their scale. The LABGEO^HC10 showed an acceptable bias for most parameters investigated. Nonequivalence for MON# is thought to be due to the difference between LH780 providing a 5-part differential and LABGEO^HC10, a 3-part differential. Limitation of LABGEO^HC10 that provides 3-part differential and no flags other than numerical flag (high or low) might require an application of broader criteria for slide review.

Our study showed that most parameters were stable for at least 24 hours at RT and at 4°C while the monocyte count was unstable at both RT and 4°C, with an unexpectedly shorter stability of refrigerated samples than for samples at RT, and opposite directional change dependent on the storage temperature, using the LAGBEO^HC10. Imeri et al¹⁷  reported that the stability of CBC parameters varied not only according to the investigated parameter but also according to storage temperature and the measurement system used. In addition, sample stability is substantially shorter than that stated by the manufacturers of hematology analyzers.^17,18  Therefore, laboratory physicians might need to validate stability before the introduction of a new hematology analyzer in their laboratories.

All parameters, except Hb, RBC, and HCT, did not show statistically significant differences according to the different EDTA tubes. In this study, we used spray-dried K₂EDTA plastic tubes and K₃EDTA plastic tubes and therefore, the previously reported dilution effect of K₃EDTA can be excluded.¹⁹  The lower MCV value of K₃EDTA-anticoagulated blood by RBC shrinkage, reported in the previous studies,^19,20  was not observed in this study. Although Hb, RBC, and HCT were statistically significantly lower in samples collected into K₂EDTA tubes than in those collected into K₃EDTA tubes, they showed excellent correlation between tubes. The differences of these parameters were minimal (<1%) and were not likely to be of any clinical relevance.

In conclusion, the overall performance of the LABGEO^HC10 is comparable to that of the LH780. The accurate results and simplicity of operation make it recommendable for small to medium-sized laboratories and applicable as a back-up instrument in larger laboratories.