An Automatic Image Based Single Dilution Method for End Point Titre Quantitation of Antinuclear Antibodies Tests Using HEp-2 Cells

Abstract

Indirect Immunofluorescence (IIF) on Human epithelial (HEp-2) cells test has been the golden standard for identifying the presence of Anti-Nuclear Antibodies (ANA) due to its high sensitivity and the large range of antigens that can be detected. Furthermore, IIF ANA test allows the positive sample strength (sample end point titre) to be reported. Despite its advantages, the IIF ANA test needs to be performed manually, and therefore it is perceived as an expensive and laborious process. This also applies to determining the strength of positive samples (end point titre) which traditionally is done by serially diluting the specimen. In this paper, we present an imagebased method which is able to automatically determine the end point titre of positive samples based only on a single screening dilution. This can be done by simulating the manual titration process using a mathematical model of the exposure-density curve. Technically, a new Image Titration Endpoint (ITE) unit based on the model is introduced. Each specimen image is then measured in terms of this unit. Finally, the end point titre for the specimen is determined through a standard curve which specifies the end point titre given an ITE unit. This process is fully automated which would give an advantage over the current digital titration methods. The overall endpoint titre agreement between the proposed approach and the manual serial dilution method in the evaluation of 134 positive samples was 100%. This high agreement demonstrates that the proposed approach is suitable for routine ANA IIF testing in the clinical settings.

Benchmarking human epithelial type 2 interphase cells classification methods on a very large dataset

“…These provide a more objective analysis which could be incorpo-14 rated into the overall test results. In recent years, we have seen significantly 15 growing interest in developing such systems [2,[10][11][12][13][14][15][16][17][18][19][20]. Nevertheless, the use 16 of private datasets with non-standard evaluation protocols makes it di cult 17 to draw meaningful conclusions from the existing works.…”

“…Nevertheless, the use 16 of private datasets with non-standard evaluation protocols makes it di cult 17 to draw meaningful conclusions from the existing works. Therefore, it is 18 critical to develop a standard evaluation platform in order to advance the 19 A c c e p t e d M a n u s c r i p t domain [2]. One notable example is the first contest initiative held in con-1 junction with the International Conference on Pattern Recognition (ICPR) 2 2012, here denoted ICPR2012Contest [2], which is then followed by publi-3 cations of a Pattern Recognition journal special issue on the same theme 4 [21].…”

“…Although at first glance the number of cell 16 images may appear significant, larger numbers of images are required 17 to draw more meaningful conclusions [2]. In fact, the overall analysis is 18 mainly a↵ected by the number of specimen images, as the cell images 19 from the same specimen are similar. More specifically, the classes in 20 both training and test sets only have two or three specimen images, 21 thus, the evaluation protocol is limited to the variation generated from 22 two specimen images.…”

“…The analysis starts by determining the specimen 17 positivity from the observed fluorescent signal. The guidelines established 18 by the Center of Disease Control and Prevention, Atlanta, Georgia (CDC) 19 suggest the use of a scoring system ranging from 0 to 4+ wherein 0 represents 20 negative (no fluorescent signal observed), and 4+ represents the strongest 21 positive (very bright fluorescent signal observed) [26]. As this process is sub-22 jective, it is possible to reduce the scoring system into merely determining 23 whether the fluorescence intensity level of the sample is positive, intermedi-24 ate or negative [12].…”

“…For the sake of brevity, the description is inten-17 tionally short so as to focus on the most relevant aspects of each method. 18 However, interested readers may find more details about each individual 19 A c c e p t e d M a n u s c r i p t …”