Evaluation of Mean Corpuscular Hemoglobin Concentration (MCHC): Comparative Performance of Automated Hematology Analyzers Versus the Gold Standard Micro-Hematocrit Method
Abstract
This study assesses the accuracy of Mean Corpuscular Hemoglobin Concentration (MCHC) measurements obtained from two automated hematology analyzers - Sysmex XN and HORIBA Yumizen H2500 - by comparing them to the gold standard micro-hematocrit derived MCHC method. The primary objective is to investigate discrepancies in MCHC values between these methodologies and to pinpoint potential sources of error within automated measurements. Findings indicate that the Sysmex XN analyzer tends to overestimate MCHC values, especially in samples with borderline or elevated MCHC. This overestimation is primarily attributed to the instrument’s underestimation of Mean Corpuscular Volume (MCV), directly affecting the calculated MCHC.
Introduction
Mean Corpuscular Hemoglobin Concentration (MCHC) is an essential red blood cell index that plays a key role in diagnosing and classifying different types of anemia. Additionally, MCHC is widely used as a quality control parameter in hematology laboratories due to its tightly controlled physiological variation.
Ensuring the accuracy of MCHC measurements is vital, as most automated hematology analyzers calculate both hematocrit and MCHC based on the measured Mean Corpuscular Volume (MCV). Consequently, any errors in MCV determination can directly affect the reliability of MCHC results.
This study is designed to evaluate how different measurement methodologies influence MCHC estimation by directly comparing results from automated hematology analyzers with those obtained using the gold standard micro-hematocrit derived MCHC method.
Materials and Methodology
Materials
- Automated Hematology Analyzers: Sysmex XN (predicate device) and HORIBA Yumizen H2500
- Micro-Hematocrit (ICSH recommended reference method)
- Routine CBC samples
Methodology
- 176 blood samples were examined on both analyzers and by the micro-HCT method.
- MCHC performance was evaluated across low, normal, borderline, and high MCHC results.
- Statistical analyses were performed to determine correlations and variability of parameters influencing MCHC estimation.
- Micro-HCT values were corrected by 1.5% to account for the known overestimation of micro-HCT compared to automated HCT.
- The following parameters were analyzed: Hemoglobin, RBC, Hematocrit, MCHC, and MCV.
Results
- Hemoglobin and RBC Correlation: both instruments showed good correlation for Hemoglobin and RBC values.
- Hematocrit Correlation: HORIBA Yumizen H2500 HCT values showed good correlation with corrected micro-HCT, while Sysmex XN HCT showed a fair but negative correlation.
Figure 1: Hemoglobin and RBC correlation between Sysmex XN and HORIBA Yumizen H2500/H1500
Good correlation of RBC & Hb parameters within both instruments.
Figure 2: Correlation of HCT from both instruments
Sysmex XN is slightly under-calibrated, points are below the desired slope. HORIBA Yumizen H2500 points are well spread and correlate with micro-HCT method.
MCHC Distribution
- In normal MCHC samples, both Sysmex XN and HORIBA Yumizen H2500 MCHC values were higher than micro-HCT derived MCHC.
- In borderline MCHC samples, Sysmex XN MCHC was significantly higher than both HORIBA Yumizen H2500 MCHC and micro-HCT derived MCHC.
- In high MCHC samples, Sysmex XN MCHC was higher than HORIBA Yumizen H2500 MCHC.
- Overall, Sysmex XN MCHC values were generally higher than HORIBA Yumizen H2500 MCHC values.
Figure 3: MCHC Distribution of all Samples
The mean value is of MCHC higher in Sysmex XN, while precision is similar when compared to HORIBA Yumizen H2500.
MCV Influence on MCHC
- Sysmex XN MCV measurements showed a negative mean value in comparison to HORIBA Yumizen H2500.
- Sysmex XN underestimated MCV as MCV increased, compared to HORIBA Yumizen H2500.
- Sysmex XN MCHC error was linked to MCV, increasing linearly with MCV groups, indicating that Sysmex XN MCHC is affected by Sysmex XN MCV underestimation.
- HORIBA Yumiwen H2500 MCHC error was not linked to MCV.
Figure 4: The distribution of Sysmex XN MCV is showing negative mean in comparison to HORIBA Yumizen H2500.
Figure 5: Sysmex XN’s slope confirms the under-estimation of MCV as MCV increases as compared to HORIBA Yumizen H2500.
Discussion and Conclusion
- The study demonstrated that the Sysmex XN analyzer consistently overestimates MCHC values, especially in borderline and high MCHC samples.
- This overestimation is primarily due to the Sysmex XN’s tendency to underestimate MCV, leading to artificially elevated MCHC calculations.
- A noticeable discrepancy in hematocrit measurements was found between the two analyzers: Sysmex XN exhibited a moderate but negative correlation with the corrected micro-HCT method, whereas the Yumizen H2500 showed a positive correlation.
- The underestimation of MCV by the Sysmex XN not only skews MCHC results but also carries important clinical consequences, such as the potential misclassification of anemia types.
- To enhance the reliability of MCHC as a diagnostic and quality control parameter, it is recommended that the causes of MCV underestimation be further investigated. Standardizing MCV measurements will help minimize these errors and strengthen the clinical interpretation of MCHC in anemia assessment and laboratory quality control.
References
- Inaccuracies Associated With the Automated Measurement of Mean Cell Hemoglobin Concentration in Dehydrated Cells By Narla Mohandas, Margaret R. Clark, Susan Kissinger, Carol Bayer, and Stephen B. Shohet : CONCISE REPORT , Blood Journal Vol.56, Issue 1, 1 July 1980, Pages 125-128
- MCHC – RED Cell Index or Quality Control Parameter ? Brain S.Bull, Raymond Aller, Berned Houwen https://www.yumpu.com/en/document/read/11586515/mchc-red-cell-index-or-quality-control-parameter-ishapd
- Hematocrit - a review of different analytical methods: Article downloaded from acutecaretesting.org
- The Comparison between Microhematocrit and Automated Methods for Hematocrit Determination, Gebretsadkan et al. Int J Blood Res Disord 2015, 2:1
- The Influence of RBC Counting Technology on MCHC Results: White Paper, Sysmex
- Mean Corpuscular Hemoglobin Concentration (MCHC) & Hematocrit (HCT) Evaluation: Observational Study on Routinely Processed Blood Samples Using Different Analytical Methods. Introduction Methods Results Conclusions. Poster ISLH 2024, Nantes, France
- Paulo SILVA, Tânia CARDOSO, Armindo GONÇALVES, Anália CARMO, Nuno SILVA Clinical Pathology Department, ULS-Coimbra, Coimbra, Portugal
Authors
Paulo Silva, Tânia Cardoso, Armindo Gonçalves, Anália Carmo, Nuno Silva
Clinical Pathology Department, ULS-Coimbra, Coimbra, Portugal