Version July 2025
| Finding | Implications |
| Initial tests for all infants | |
| Comprehensive metabolic panel | |
| To evaluate for conjugated hyperbilirubinemia (cholestasis) versus unconjugated hyperbilirubinemia. |
| To assess for hepatocyte injury. |
| To assess for biliary injury. Furthermore, several genetic/metabolic disorders can be divided into high- and low-GGTP categories¶. |
| To assess hepatocyte function. Low albumin suggests poor nutrition, renal losses, or poor hepatic synthetic function. |
| To assess for metabolic disease. Abnormalities in these results are often seen in infants with metabolic disease. |
| CBC with differential | To assess for infection and/or splenic sequestration. Elevated WBC is suggestive of infection. Low WBC and platelet count could indicate portal hypertension (with splenic sequestration). |
| PT/INR and PTT | To assess hepatocyte function and/or vitamin K deficiency. Abnormal results indicate impaired liver synthetic function and/or vitamin K deficiency. |
| Additional tests to evaluate for systemic illness or specific liver diseasesΔ | |
| Urinalysis and urine culture | Appropriate for most infants with cholestasis to exclude urinary tract infection and to evaluate possible kidney involvement. |
| Blood culture | If clinical presentation suggests sepsis. |
| Evaluation for TORCH infections | Evaluation depends on suspicion including clinical presentation:
|
| Urine-reducing substances | Screen for galactosemia (in infants ingesting lactose)§. |
| Urine succinylacetone | Screen for tyrosinemia. |
| Serum bile acids | Elevations are diagnostic of cholestasis. Serum bile acids will be low in infants with bile acid synthetic disorders. |
| Alpha-1 antitrypsin concentration | |
| Low levels suggest alpha-1 antitrypsin deficiency. Normal levels do not exclude alpha-1 antitrypsin deficiency, because this is an acute phase reactant. |
| The primary alleles associated with liver disease are PI*ZZ homozygosity or PI*SZ heterozygosity. |
| TSH, T4 | Screen for congenital hypothyroidism (primary or central). |
| ACTH, cortisol | Screen for adrenal insufficiency and hypopituitarism. |
| Serum ferritin, iron profile including iron, transferrin | Elevations suggestive of gestational alloimmune liver disease and hemophagocytic lymphohistiocytosis. |
| Urine bile acid analysis by FAB-MS | Screen for BASD, which may present with low-GGT cholestasis¥. |
| Metabolic testing | If a metabolic disorder is suspected, initial screening includes creatine kinase, plasma amino acids, urine organic acids, acylcarnitine profile, ammonia, lactate:pyruvate ratio. |
| Genetic testing | Genetic testing is rapidly evolving with the availability of new technologies‡. It may include karyotype, targeted gene panels, and/or whole-exome sequencing. |
ACTH: adrenocorticotropic hormone; ALT: alanine aminotransferase; AST: aspartate aminotransferase; BASD: bile acid synthetic defects; CBC: complete blood count; CMV: cytomegalovirus; CSR: compartmentalized self-replication; FAB-MS: fast atom bombardment mass spectrometry; GGT: gamma-glutamyl transferase; GGTP: gamma-glutamyl transpeptidase; Ig: immunoglobulin; INR: international normalized ratio; PCR: polymerase chain reaction; PT: prothrombin time; PTT: partial thromboplastin time; T4: thyroxine; TORCH: toxoplasmosis, others (including syphilis, varicella), rubella, cytomegalovirus, and herpes simplex virus; TSH: thyroid-stimulating hormone (thyrotropin); WBC: white blood cell.
¶ GGTP is disproportionately elevated (compared with AST and ALT) in the most common types of neonatal cholestasis, including biliary atresia and Alagille syndrome, while a normal or low GGTP is seen in most forms of progressive familial intrahepatic cholestasis, BASD, and arthrogryposis-renal dysfunction-cholestasis syndrome.
Δ These tests are selected based on the clinical presentation and results of initial tests.
◊ Serologic tests for CMV (ie, IgG and IgM antibodies) are not recommended for the diagnosis of congenital CMV. CMV IgM is positive in only 50 to 80% of newborns with confirmed congenital CMV based on urine PCR[1].
§ Urine-reducing substances is only valid as a screen for galactosemia if the infant is fed breast milk or a cow's milk-based formula (which contains lactose, then hydrolyzed to galactose).
¥ Infants must be off of ursodeoxycholic acid for at least 5 days prior to urine collection for bile acid analysis because the FAB-MS signature of the drug overlaps with some of the abnormal bile acid metabolites seen in BASD.
‡ Individual gene sequencing can be done if the clinical presentation suggests a specific diagnosis, such as Alagille syndrome. For screening of multiple genes associated with inherited cholestasis, next-generation sequencing panels are available. Each panel interrogates approximately 20 to 70 genes. Current information is available at GeneTests.org.
