Lab Med Online.  2021 Jul;11(3):171-176. 10.47429/lmo.2021.11.3.171.

Re-evaluation of the Utility of the CH50 Test Using Liposome Immunoassay

• Lee J
• Jearn LH
• Kim TY

• KMID: 2526062
• DOI: http://doi.org/10.47429/lmo.2021.11.3.171

Abstract

Background
This study aimed to evaluate whether the 50% hemolytic complement (CH50) is a suitable screening test to investigate complement activity by comparing its liposomal immunoassay-based results with C3 and C4 values and determine if it meaningfully reflects changes in the complement system.
Methods
A retrospective study was conducted on 35,908 test samples that were simultaneously evaluated using C3, C4, and CH50 assays. Liposomal immunoassay was used for CH50 test, and rate nephelometry or immunoturbidimetry was used for C3 and C4 tests. The CH50, C3, and C4 results were divided into low, normal, and high groups for comparison and analysis. The distribution of C3 and C4 measurements according to the three different CH50 groups was analyzed.
Results
Of the 35,908 cases, the C3 and C4 results were decreased in 19,051 (53%) and 14,666 (41%) cases, respectively. However, CH50 results were decreased in 6,257 cases (17%), which were lower than those for C3 and C4. A statistically significant difference was observed in the distribution of C3 and C4 values among different CH50 groups (P < 0.001).
Conclusions
The CH50 test based on the liposome immunoassay does not sensitively reflect the decrease in C3 and C4. However, it tends to show a better decrease at low concentrations proportional to the decreased amount of C3 and C4. Hence, it can be useful for severe complement deficiency screening. Therefore, there are limitations with the use of the CH50 test alone for the screening of complement activity, and care should be taken during result interpretation.

Keyword

CH50; Liposome immunoassay; Complement; C3; C4

Figure

• 

  Fig. 1 The box plot and Man-Whitney comparison of C3 or C4 values with CH50 low, normal, and high groups in subgroup 1 (A), (B), subgroup 2 (C), (D), and total (E), (F). Abbreviation: CH50, 50% hemolytic complement.

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