Homocysteine: A New Diagnostic Marker in Spontaneous Bacterial Peritonitis

Eur J Gastroenterol Hepatol. 2018 Jul;30(7):779-785. doi: 10.1097/MEG.0000000000001109.


Background and aims: The diagnosis of spontaneous bacterial peritonitis (SBP) depends primarily on a polymorphonuclear leukocyte cell count more than 250/mm. This method is invasive, and not diagnostic in all variants of SBP; we aimed to assess serum homocysteine as a precise indicative marker for the diagnosis of all variants of SBP.

Patients and methods: A total 323 consecutive ascitic patients were registered in this prospective work. Serum and ascitic fluid of homocysteine were evaluated utilizing an enzyme-linked immunosorbent assay.

Results: Participants were classified into a non-SBP group, including 262 participants and 61 patients with SBP. Serum and ascitic homocysteine were considerably elevated in the SBP group than in the non-SBP group (17.94±7.57 vs. 11.75±5.68 μmol/l; P<0.001 and 14.70±5.45 vs. 9.75±4.55 μmol/l; P<0.001). At a cutoff value of 17.79 μmol/l, serum homocysteine had 89.3% specificity and 95.1% sensitivity for distinguishing SBP (area under the curve: 0.932) and, at a cutoff value of 16.1 μmol/l, ascitic homocysteine had 84.4% specificity and 92.7% sensitivity for distinguishing SBP (area under the curve: 0.901). Both were positively correlated with the polymorphonuclear count, C-reactive protein, Child-Pugh score, and Model For End-Stage Liver Disease score as well as negatively correlated with the protein content in the ascitic fluid and estimated glomerular filtration rate. After SBP therapy, there was a marked reduction in serum and ascitic homocysteine levels.

Conclusion: This study demonstrates that serum and ascitic homocysteine are considerably higher in SBP participants versus non-SBP patients. Serum homocysteine may provide a reliable and noninvasive diagnostic marker for all variants of SBP.

MeSH terms

  • Aged
  • Anti-Bacterial Agents / therapeutic use
  • Area Under Curve
  • Ascitic Fluid / metabolism
  • Bacterial Infections / blood*
  • Bacterial Infections / diagnosis*
  • Bacterial Infections / drug therapy
  • Bacterial Infections / microbiology
  • Biomarkers / blood
  • Enzyme-Linked Immunosorbent Assay
  • Female
  • Homocysteine / blood*
  • Humans
  • Male
  • Middle Aged
  • Peritonitis / blood*
  • Peritonitis / diagnosis*
  • Peritonitis / drug therapy
  • Peritonitis / microbiology
  • Predictive Value of Tests
  • Prospective Studies
  • ROC Curve
  • Reproducibility of Results
  • Time Factors
  • Treatment Outcome
  • Up-Regulation


  • Anti-Bacterial Agents
  • Biomarkers
  • Homocysteine