Population-based screening using stool color cards has emerged as one of the most impactful public health interventions for early detection of BA. This strategy is based on a simple but highly relevant clinical sign: persistent acholic or hypocholic stools, which reflect impaired bile flow and often precede other manifestations of cholestatic liver disease. Large-scale programs implemented in regions such as Taiwan and Japan have consistently demonstrated that stool color card screening reduces the age at diagnosis and at KPE, with corresponding improvements in jaundice clearance and native liver survival [13–16] The reported sensitivity of SCC screening ranges between 76% and 90%, while specificity is consistently high, close to 99.9% [17,18] Notably, comparable reductions in age at portoenterostomy have also been achieved in large population-based cohorts through healthcare system centralization alone, even in the absence of formal population screening programs, highlighting the critical role of organized referral pathways and early specialist access [7]

The strength of stool color card screening lies in its simplicity, low cost, and scalability. It is considered a cost-effective strategy in settings where it has been systematically implemented and evaluated, like Taiwan and Japan. Although the stool color card has been shown to be cost-effective in settings where it has been systematically implemented and evaluated, such as Taiwan and Japan, robust cost-effectiveness data from Europe and low- and middle-income countries remain limited. Implementation requires professional training, integration into primary care workflows, and reinforcement of educational strategies, as the lack of awareness about BA among healthcare providers remains a barrier [13] And importantly, the effectiveness of stool color card programs is not solely dependent on sensitivity for BA but also on the ability to trigger timely medical evaluation and referral pathways once abnormal stools are identified.

Despite these advantages, stool color card screening is not without limitations. Variability in caregiver interpretation, transient stool color changes, and reduced sensitivity in the earliest neonatal period may lead to false reassurance or delayed recognition in some cases. Additionally, successful implementation requires integration into broader healthcare systems, including education of parents, training of primary care providers, and streamlined referral networks. In regions without structured screening programs, reliance on stool color alone remains inconsistent, contributing to ongoing delays in diagnosis.

In addition to stool color card programs, laboratory-based newborn screening strategies have been evaluated as complementary approaches for early identification of BA. A large multicenter prospective study conducted in the United States enrolled more than 124,000 newborns and applied a two-stage screening protocol based on direct or conjugated bilirubin measurements. This strategy demonstrated excellent diagnostic performance, with a reported sensitivity of 100%, specificity of 99.9%, and negative predictive value of 100% [19] These findings support the biological and clinical rationale for incorporating early bilirubin assessment into neonatal screening pathways, particularly in healthcare systems where universal laboratory screening is already established. However, implementation requires robust follow-up algorithms, standardized cut-off values, and careful consideration of false-positive rates and resource utilization [19] Nevertheless, for a clinician confronted with a jaundiced newborn, personal observation of the stools and measurement of direct bilirubin are the most reliable signs for diagnosis of cholestasis and suspicion of BA.

Liver biopsy remains an established component of the diagnostic evaluation of persistent neonatal cholestasis and is widely used when BA is suspected [26] Percutaneous liver biopsy is the preferred approach in most centers; however, it should be incorporated into diagnostic pathways in a manner that does not delay surgical exploration when clinical suspicion is high [38,39]

When interpreted by experienced pathologists, liver biopsy distinguishes obstructive cholangiopathies such as BA from intrahepatic causes of cholestasis in approximately 90–95% of cases [26,40] Reported sensitivity varies from 60% to 95%, depending on patient age and histopathologic expertise [41] Typical histologic features include ductular proliferation, bile plugs, portal edema, and portal fibrosis, usually with preservation of lobular architecture. However, histologic findings may be heterogeneous, particularly early in the disease course.

In the multicenter ChiLDReN Consortium study of 227 biopsies, liver biopsy demonstrated a sensitivity of 88% and a specificity of 90.1%; notably, ductular proliferation was absent in 22.8%, and bile plugs in 25% of confirmed BA cases, underscoring the variability of early histologic presentation [40] Sequential biopsy studies further illustrate the temporal evolution of histologic features, which are frequently absent around 40 days of age but become more consistently detectable after 60 days [42]

Meta-analyses confirm high overall diagnostic performance, with sensitivity ranging from 88% to 96% and specificity from 91% to 100%, with the highest yield reported in infants ≤60 days of age, in whom both sensitivity and specificity exceed 95% [41] Although invasive, major complications are uncommon, occurring in approximately 0.5–4% of procedures, particularly in the presence of coagulopathy, very young age, or advanced liver disease [43,44,45]

Overall, liver biopsy provides valuable diagnostic and prognostic information in BA, particularly when noninvasive methods are inconclusive. Its limitations in very early disease highlight the importance of interpreting histologic findings within an integrated clinical, laboratory, and imaging framework, and of embedding biopsy into diagnostic pathways that prioritize timely surgical intervention.

Intraoperative cholangiography is widely regarded as the reference standard for establishing or excluding BA in infants with persistent cholestasis. It is typically performed as the final diagnostic step immediately before KPE, particularly when noninvasive investigations and liver biopsy do not provide a definitive diagnosis, but clinical suspicion remains high. By directly visualizing the extrahepatic biliary tree, intraoperative cholangiography allows real-time surgical decision-making and, in many centers, is performed using minimally invasive approaches that permit portoenterostomy during the same operative session when BA is confirmed [26,38,46,47]

Accurate interpretation of intraoperative cholangiography is critical, as several non–BA cholestatic disorders may be associated with hypoplastic or poorly opacified bile ducts. Alagille syndrome, neonatal sclerosing cholangitis, and, less frequently, cystic fibrosis are among the conditions most commonly reported to mimic the cholangiographic appearance of BA, increasing the risk of false-positive interpretation [26,38,46,47] In addition, some patients with these pathologies frequently show transient acholic stools. Preoperative clinical and genetic evaluation is therefore essential to contextualize intraoperative findings and reduce diagnostic error. Importantly, multiple studies have demonstrated unfavorable outcomes when KPE is performed in infants with Alagille syndrome [48,49] These observations were reinforced by the multinational GALA study, which confirmed poorer outcomes in this population, further emphasizing the need to avoid portoenterostomy when an alternative diagnosis is likely [50]

Taken together, these data underscore the importance of expert interpretation of intraoperative cholangiography within an integrated diagnostic framework that incorporates clinical features, preoperative investigations, and genetic considerations, thereby minimizing unnecessary surgical intervention and its associated risks.

Hepatobiliary scintigraphy (HBS) using Tc-99m–labeled iminodiacetic acid derivatives has historically been used to assess biliary patency in cholestatic infants [26,27] Although reported sensitivity is high—approaching 98–99% in meta-analyses—specificity is consistently limited, typically ranging from 45% to 75% [51] Absent tracer excretion may also occur in several intrahepatic cholestatic disorders, including idiopathic neonatal hepatitis, interlobular bile duct paucity, and parenteral nutrition–associated cholestasis, resulting in frequent false-positive interpretations [52,53] In a comparative study, HBS achieved 88% sensitivity but only 46% specificity, with an overall accuracy of 67%, whereas liver biopsy demonstrated superior performance (100% sensitivity, 94% specificity, and 97% accuracy) [54]

Elastography assesses liver stiffness, which primarily reflects fibrosis and, at later stages, portal hypertension. In BA, stiffness values are consistently higher than in other cholestatic conditions; however, this difference largely reflects progressive structural injury rather than the earliest stages of disease [20,55]

Individual studies report moderate to high diagnostic accuracy, with marked age dependency. In a multicenter cohort, transient elastography showed excellent performance in infants ≤ 90 days, yet stiffness closely correlated with histologic fibrosis [56] Similarly, shear-wave elastography demonstrated an AUROC of 0.82 in infants ≤ 45 days, with improved performance in older infants [57] Meta-analyses report pooled sensitivities of 77–86% and specificities of 79–86%, with accuracy increasing as fibrosis advances, but inferior to highly specific grayscale ultrasound markers such as the triangular cord sign or gallbladder abnormalities [30,58]

Overall, elastography provides complementary information but has limited value for early diagnosis, given its dependence on disease progression and overlap with other inflammatory or cholestatic conditions.

MRCP has been evaluated as a noninvasive method to visualize the extrahepatic biliary tree, typically relying on no visualization of ducts or gallbladder abnormalities [59] However, diagnostic performance is limited in neonates and young infants. In a pilot study, extrahepatic bile ducts were visualized in only 50% of infants younger than 30 days and 62.5% of those older than 3 months [60]

Meta-analyses demonstrate relatively high sensitivity but consistently low specificity, often below 40%, leading to frequent false-positive results [53] In a prospective cohort, three-dimensional MRCP achieved sensitivity near 99% but specificity of only 36% [61] Technical constraints, including small duct caliber, motion artifacts, frequent need for sedation, cost, and limited availability, further restrict its role in early diagnostic pathways [26,27]

Early surgical intervention with KPE remains the single most important determinant of native liver survival in BA. Across multiple cohorts and registries, age at surgery consistently emerges as the strongest prognostic factor. A meta-analysis including nine large cohorts demonstrated that KPE performed early—particularly within the first 30 days of life—was associated with significantly improved native liver survival at 5, 10, and even 20 years, whereas later surgery was linked to a more than twofold increased hazard for liver transplantation (hazard ratio 2.12) [68]

These findings are supported by data from the Western Pediatric Surgery Research Consortium, which estimated a 2% decline in transplant-free survival for each additional day of surgical delay [69] Although the traditional “60-day dogma” has been challenged, outcomes remain consistently superior when surgery is performed before 30–45 days [70] Registry data reinforce this time dependency: in the Japanese national registry, 25-year native liver survival was 35% among infants operated before 31 days compared with 25% in those treated later [71] Similar trends were observed in a large European cohort of more than 1,400 patients, in which earlier surgery was associated with higher rates of jaundice clearance [8]

Despite widespread recognition of BA as a surgical emergency, delays in diagnosis and referral persist globally. It has been well known for decades that BA is a surgical emergency. More recently, Lacaille and colleagues reinforced in a Delphi consensus that reducing time to diagnosis remains a major objective of BA care, as delays directly compromise outcomes [72] Davenport et al. provided evidence that centralization of BA care in specialized centers leads to earlier referral, lower median age at surgery, and improved postoperative outcomes [7] Population-based studies confirm disparities in timing and prognosis across regions. A Saudi Arabian national study (2000–2018) reported that the median age at KPE remained above the optimal threshold, with native liver survival significantly lower compared to countries with centralized care systems [73] Similarly, US registry data indicate that many children still undergo surgery after 60 days, highlighting the urgent need for public health strategies to improve early recognition and referral [74] Reports from resource-limited settings also confirm that even in constrained systems, earlier surgery translates into better outcomes [75]

Despite early KPE improving transplant-free survival, long-term follow-up shows that complications such as portal hypertension and cholangitis remain common, requiring lifelong monitoring [76] Clearance of jaundice within three months postoperatively is a strong predictor of 5-year native liver survival [77] Isolated reports of extremely early KPE (within the first 2 weeks of life) demonstrate dramatic improvements in prognosis, including normalization of liver function and avoidance of early transplantation [78,79]

Cholangitis is the most frequent complication following KPE, affecting approximately 40–93% of children with BA, with most episodes occurring within the first two years of life [80,81] Both early and recurrent cholangitis have been consistently associated with poorer jaundice-free and native liver survival. Diagnostic definitions usually combine clinical features — such as fever, worsening jaundice, acholic stools, and abdominal discomfort—with laboratory and imaging findings, including inflammatory markers, rising transaminases, bilirubin, gamma-glutamyl transferase, or bile lakes [80]

The rationale for short-term antibiotic prophylaxis in the immediate postoperative period is to prevent early cholangitis, a complication strongly linked to adverse outcomes. Oral regimens such as trimethoprim–sulfamethoxazole or neomycin administered for 6–12 months have been used as primary or secondary prophylaxis in some centers [82,83] However, potential benefits must be weighed against the risk of selecting resistant organisms and severe infections. Empirical choices have evolved over time, shifting from third-generation cephalosporins toward broader-spectrum agents in resistant cases [83] Regional data indicate that gram-positive organisms, particularly Enterococcus species, may account for nearly 50% of late cholangitis episodes, further complicating empirical strategies [84]

Despite widespread clinical use, evidence supporting routine prophylaxis remains conflicting. A systematic review including 714 patients found no significant reduction in cholangitis incidence or improvement in native liver survival [82] These findings were confirmed by subsequent meta-analyses [85] Randomized controlled data are limited; one trial showed reduced early-onset cholangitis with prolonged intravenous antibiotics but no improvement in jaundice clearance or long-term survival [86] Retrospective studies have similarly failed to demonstrate consistent benefit [87–89] Overall, while short-term prophylaxis may reduce very early cholangitis in selected settings, robust evidence supporting routine use in all patients is lacking.

Off-label use of ursodeoxycholic acid (UDCA) following KPE is routine in many centers worldwide, with surveys from Europe and Japan reporting near-universal adoption [90,91] Proposed mechanisms include modulation of bile acid composition, stabilization of hepatocyte membranes, stimulation of bicarbonate-rich hypercholeresis, cholangiocyte protection, and immunomodulatory effects [91]

Clinical data regarding UDCA after KPE suggest biochemical benefit but remain inconclusive with respect to long-term clinical outcomes. A crossover withdrawal study demonstrated deterioration in liver biochemistry following UDCA discontinuation, with subsequent improvement upon reintroduction, supporting a pharmacologic effect on bile flow and cholestasis markers [92] In contrast, concerns regarding potential harm have largely been derived from experimental or mechanistic hypotheses rather than robust clinical evidence. While molecular studies have suggested theoretical adverse effects of prolonged bile acid exposure, clinically significant toxicity attributable to UDCA has not been consistently reported in pediatric BA cohorts [93] More recent multicenter observational data indicate that low-dose UDCA (≤ 10 mg/kg/day), particularly during the first year after KPE, may be associated with improved bilirubin and bile acid profiles, whereas prolonged use beyond 12–36 months does not appear to confer additional benefit [94]

Systematic reviews in pediatric cholestasis consistently report improvement in liver biochemistry and pruritus, but no definitive effect on native liver survival [95] Combination strategies with corticosteroids may accelerate early jaundice clearance, although the independent contribution of UDCA is unclear [96] Importantly, in cases of Kasai failure, continuation of UDCA is generally discouraged due to the risk of bile acid accumulation and complications [97,98]

Taken together, UDCA remains widely used as supportive therapy after KPE, with a favorable safety profile and biochemical benefits, although high-quality evidence demonstrating improvement in long-term transplant-free survival is lacking.

Phenobarbital has historically been used as a choleretic agent in infants with cholestasis, including those undergoing KPE. However, available evidence does not support its routine postoperative use. Randomized trials failed to demonstrate clinical benefit, [99,100] and comparative studies showed limited efficacy in reducing direct bilirubin, with no improvement in outcomes compared to UDCA [101]

Earlier reports suggesting benefit as part of combination regimens likely reflected the effects of corticosteroids or UDCA rather than phenobarbital itself [102] In the absence of demonstrated efficacy and given concerns regarding potential neurotoxicity in early life, phenobarbital has no established role in the postoperative management of BA.

N-acetylcysteine has been explored as an adjunctive therapy after KPE due to its antioxidant and hepatoprotective properties and its ability to stimulate glutathione synthesis and bile flow [99] However, current evidence does not support its routine use [103] Although generally well tolerated, the lack of efficacy precludes its incorporation into routine postoperative care. Broader perioperative literature similarly fails to demonstrate consistent benefit [104–106] At present, N-acetylcysteine should be considered investigational and not part of routine clinical care

Inflammation has long been implicated in the pathogenesis of BA, leading to the hypothesis that corticosteroids could enhance bile drainage after KPE. Nevertheless, the role of adjuvant corticosteroid therapy following Kasai portoenterostomy for biliary atresia remains a subject of ongoing debate.

The multicenter Steroids in Biliary Atresia Randomized Trial (START) demonstrated that high-dose corticosteroids (intravenous methylprednisolone 4 mg/kg/day for 2 weeks followed by oral prednisolone 2 mg/kg/day for 2 weeks with subsequent tapering over 9 weeks) initiated within 72 hours of hepatoportoenterostomy failed to significantly improve bile drainage at 6 months post KPE (58.6% versus 48.6% in placebo group; adjusted relative risk 1.14, 95% confidence interval 0.83-1.57; p = 0.43) or transplant-free survival at 24 months of age (58.7% versus 59.4%; adjusted hazard ratio 1.0, 95% confidence interval 0.6-1.8; p = 0.99). Moreover, steroid therapy was associated with an earlier onset of serious adverse events by 30 days post-KPE (37.2% versus 19.0%; p = 0.008), including complications at surgical anastomoses and intestinal perforation [107]

A subsequent Cochrane systematic review and meta-analysis corroborated these findings, concluding that glucocorticosteroids after Kasai portoenterostomy do not result in statistically significant treatment differences in bile drainage at 6 months, although a small clinical benefit could not be excluded [108]

More recent meta-analyses have suggested potential benefits in specific subgroups, particularly infants undergoing Kasai portoenterostomy at less than 70 days of age, with improved jaundice clearance rates at 6, 12, and 24 months (risk ratio 1.35, 95% confidence interval 1.18-1.55; p < 0.001 at 6 months) and improved native liver survival at 24 months (risk ratio 1.31, 95% confidence interval 1.03-1.68; p = 0.028), though short-term native liver survival and cholangitis incidence remained unaffected [109]

Newer strategies, including rectal budesonide, remain experimental and require further validation [110] Steroid pulse therapy has also been proposed for infants with poor postoperative reduction in bilirubin levels, although supporting data are limited [111]

The heterogeneity in steroid regimens, dosing protocols, and patient populations across studies continues to complicate definitive conclusions, though the preponderance of high-quality evidence does not support routine adjuvant corticosteroid use in the immediate postoperative period following Kasai portoenterostomy for biliary atresia [1,112–114]

Overall, corticosteroids are not used routinely after KPE but may be considered in carefully selected and well-evaluated cases, particularly in younger infants or those with suboptimal early bile drainage.