Quantitative resultsComparison of the FA280 and the KK for parasite detection

A total of 1000 participants provided stool samples, including 478 (47.8%) males and 522 (52.2%) females. The age distribution was as follows: < 20 years (17.3%), 20–39 years (20.9%), 40–59 years (29.2%), and ≥ 60 years (32.6%). The overall average EPG was 12.35. Males (13.6%) had a higher positive rate than females (6.7%). Participants in the 40–59 age group had the highest positive rate (14.0%), while the < 20 age group had the lowest positive rate (6.4%). No statistically significant differences in positive rates between the two methods were observed across different age and gender groups (Pearson’s Chi-square test, P > 0.05) (Table 1). The FA280 and the KK method both showed a 10.0% overall positive rate for C. sinensis. There was no statistically significant difference between the two methods (McNemar’s test, P > 0.999) (Table 2). The overall agreement rate was 96.8%, with highly acceptable agreement (\(\kappa\) = 0.82, 95% CI: 0.76–0.88). Figure 2 showed high-resolution images with 5 million pixels from the FA280 digital microscope depicting eggs of C. sinensis. The figures regarding the collection tube, sample detection, and results output of the FA280 could be found in Additional file 3.

Table 1 The demographic characteristics and infection details of the study subjectsTable 2 Results of the FA280 and the Kato-Katz method for C. sinensis infection diagnosisFig. 2

High-resolution images from the FA280. A–C were C. sinensis eggs (red circles)

Relationship between the consistency of positive results and the infection intensity

The agreement rate of positive results between the FA280 and the KK method in the group with low infection intensity was significantly higher than that in group with high infection intensity (Pearson’s Chi-square test, P < 0.05), regardless of the chosen cut-off values and group counts (Table 3).

Table 3 The consistency of positive results between the FA280 and the Kato-Katz method across different infection intensity groups under different cut-off valuesQualitative resultsFindings on differences between the FA280 and the KK methods

Three health service staff participated in this study. All participants were female. The average years of working experience for control and fecal examination of clonorchiasis was 20.3 years. Demographic details of interviews are provided in Additional file 2.

Differences between the FA280 and the KK methods were analyzed thematically around (Table 4): (i) differences in testing procedures; (ii) differences in detecting results; and (iii) differences in acceptance

Table 4 Overview of themes and subthemes relative to differences between the FA280 and the Kato-Katz method

Theme 1: differences in testing procedures.

Feeling about the testing process

All participants considered the KK method’s testing process to be complex and cumbersome, although it was relatively easy to learn. However, they pointed out that the FA280 was straightforward, and easier to master than the KK method for detecting C. sinensis.

“The KK method is a bit cumbersome to operate.”

“The KK method is easy to learn.”

“The operation of the fecal analyzer is quite simple. Once the samples are collected, you place them directly into the instrument and let it do the rest.”

“Learning to use the fecal analyzer is much easier compared to the KK method.”

Laboratory environment

Every participant mentioned that the KK method created a dirty and smelly environment. In contrast, the FA280 had less odor and one participant emphasized that the operating environment for the fecal analyzer was very sanitary.

“During the preparation of KK smears, there is an odor, and the environment is not pleasant, quite dirty, and smelly. Then, during the process of examining the smears, as it involves using a microscope and looking at them with the naked eye, there is still an odor, and the environment is not pleasant either.”

“Both the fecal analyzer and the KK method have odors, so how could there be no smell? However, the KK method has a stronger odor, while the instrument has less odor.”

“The environment is excellent, and using fecal analyzer is very clean.”

Time requirement

All participants remarked that the KK method was time-consuming and slow, whereas the FA280 analyzer was much faster and more efficient due to its high throughput.

“Examining 200 samples using the KK method could take a week for just one person; it’s quite slow-paced.”

“Examining 200 samples with the fecal analyzer might take just over an hour.”

“The KK method requires more time; the FA280 takes shorter because the analyzer conducts tests on multiple fecal samples concurrently.”

Smear examination

When examining the smears with the KK method, participants had to identify eggs by naked eyes and manually count the number. In contrast, the FA280 could automatically identify and capture images of eggs across more fields of view, and then record the results. However, the current analyzer was unable to perform automatic counting.

“You have to manually count and calculate by drawing tally marks.”

“The analyzer is capable of automatically capturing images and recording.”

“The analyzer does not support automatic counting at present.”

“The FA280 offers multiple visual fields.”

Requirement for technicians

In contrast to the FA280, the requirement for technicians of the KK method was much stricter. Participants expressed the need for professional training to become proficient in using the KK method. One participant added that the KK method also demanded higher qualifications from technical personnel, such as a solid background in medicine and adequate experience in the laboratory. Hence, those without lab experience require much longer training to master the KK method.

“Using the KK method for fecal testing generally requires professional training.”

“Mastering the KK method typically takes about one day for individuals with prior laboratory testing experience, whereas it may require approximately a week for those without any prior experience in laboratory testing.”

“The KK method for smear examination demands stringent requirements on the technicians. It requires a wide-ranging professional knowledge, especially in the identification of different parasite eggs. In addition, sufficient experience and adequate training time are also important.”

“The fecal analyzer is fully automated. Whatever it sees, it automatically displays, identifies, and records. It’s more user-friendly.”

Theme 2: differences in detecting results.

Accuracy

Two participants raised concerns about the potential for missed detections with the KK method. They believed that the fecal analyzer had a higher detection rate and provided more accurate results.

“Using the KK method needs examining smears under a microscope, and sometimes adjusting the fine focus can lead to easily missing parasite eggs.”

“The fecal analyzer can detect a higher number of eggs compared to manual observation, leading to a higher detection rate.”

“I personally feel the machine is more accurate.”

Involvement of human factor

Three participants agreed that the results obtained from the KK method relied on the subjective judgment of the technicians, and the capacity of human focus was limited. These factors could result in human errors. In contrast, the FA280 was less affected by human factors and required only manual calibration before initial use. Additionally, all participants mentioned that after the automatic identification by the fecal analyzer, results could be manually reviewed and adjusted.

“The KK method relies on manual visual inspection, which is affected by subjective influences, while the fecal analyzer can automatically identify. When humans observe the smears, there’s always a possibility of fatigue and some human error.”

“But the fecal analyzer still needs calibration.”

“The results it produces need manual verification to confirm them. Sometimes false positives or false negatives may occur, so we have to manually review the images of the eggs it captures and check them with our naked eye.”

Infection intensity

All participants stated that the KK method allowed for both qualitative and quantitative analysis, enabling infection intensity quantification. While the fecal analyzer could not yet quantify infection intensity, participants were confident that the establishment of standardized protocols could make it feasible.

“The KK method allows for both qualitative and quantitative analysis.”

“It cannot calculate for quantitative analysis now (by the fecal analyzer).”

Theme 3: differences in acceptance.

Acceptability

One participant mentioned that using the KK method was currently a last resort option, and all participants expressed a preference for using the fecal analyzer for stool examination.

“Even though we may not fully accept the KK method, we have to acknowledge its importance, as it was the best available method in the past. Additionally, the World Health Organization recommends this method.”

“I'm willing to accept the fecal analyzer. I think it's excellent.”

Future choice

All participants demonstrated their desire to utilize the FA280 in their future work. Moreover, one participant advocated for wider adoption of this technology.

“In future work, I prefer to use the fecal analyzer.”

“I hope to promote the adoption of fecal analyzers, reducing the dependency on the KK method as the primary approach.”

Findings on the promotion of the FA280

The qualitative data from two medical institution administrators were categorized into three themes (Table 5): (i) advantages of promotion; (ii) challenges of promotion; and (iii) suggestions for promotion.

Table 5 Overview of themes and subthemes about the promotion of the FA280

Theme 1: advantages of promotion.

For medical institutions

All administrators agreed that the widespread use of the FA280 could significantly increase the quantity, efficiency, and quality of clonorchiasis detection. Moreover, one noted its potential financial benefits for lab medicine.

“The fecal analyzer can increase the number of examinations conducted, and enhance the level of detection.”

“Clonorchiasis is just one aspect; the detection levels as well as the detection efficiency of other diseases requiring fecal examination can also be improved.”

“Indeed, it can also generate revenue for certain departments in hospitals, thereby providing them with financial benefits.”

For population

An administrator pointed out that promoting the FA280 could increase the chances of diagnosing clonorchiasis in the population, thereby improving treatment opportunities.

“Sometimes, clinical physicians may overlook the commonality of clonorchiasis and therefore do not suggest the relevant examinations. The FA280 can automatically identify components in feces, which increases the diagnostic chances for patients with this disease.”

“Accordingly, hospitals can provide treatment for individuals with positive test results.”

Theme 2: challenges of promotion.

From fecal analyzer

One administrator expressed concerns about the lack of standardized calibration procedures for the FA280. Furthermore, the high cost of the analyzer and the absence of uniform pricing for patients’ testing services were highlighted by the other administrator.

“The data isn’t shared at the moment; each machine is calibrated individually.”

“The entire instrument may be relatively expensive, costing several hundred thousand.”

“Currently, the challenge revolves around pricing for each testing service. There isn’t an appropriate pricing scheme. However, if a reasonable charge based on the cost is determined, the FA280 could be more easily promoted in the clinical practices and general hospitals.”

Public attitude

An administrator also mentioned that the low awareness among the public regarding detecting and the insufficient attention from the government to clonorchiasis hindered the widespread adoption of the FA280.

“There is a lack of awareness among the general population about clonorchiasis, leading to insufficient screening awareness.”

“The government does not pay enough attention to clonorchiasis.”

Theme 3: Suggestions for promotion.

Scope of promotion

All administrators believed that the scope of FA280 promotion varied depending on the prevalence of clonorchiasis in different regions. Medical institutions in high-prevalence areas could commonly be equipped with the fecal analyzer, but in low-prevalence areas, only a limited number of comprehensive hospitals needed it.

“In highly endemic areas with clonorchiasis like the Pearl River Delta, it would be better for medical institutions capable of professional examination for parasites to have at least one of this kind of analyzers.”

“In my opinion, comprehensive hospitals in areas with low prevalence should universally adopt this analyzer.”

Improvement for the fecal analyzer

Due to the unavailability of shared calibration data for the analyzers at present, an administrator suggested the proposed unifying and sharing calibration standards. In addition, the importance of establishing standardized criteria for quantitative testing to determine the infection intensity was emphasized.

“Theoretically, it’s feasible to share calibration data. Previously well-calibrated data obtained by sharing could be pre-loaded before the instrument leaves the factory. However, this requires cooperation with the manufacturer, and we have not yet achieved it.”

“For instance, we could fix the fecal weight in the sampling tubes. Then, for a total of 100 images captured, we could randomly select 20 images. The number of images containing C. sinensis eggs among these 20 could serve as a standardized measure of infection intensity.”