{
  "id": "kaiser-sepsis",
  "version": "b046f33692b6",
  "status": "published",
  "name": "Kaiser Sepsis Calculator",
  "question": "What is my baby’s Kaiser sepsis risk?",
  "summary": "Estimates a newborn’s risk of early-onset sepsis per 1,000 births from maternal factors with the Kaiser Permanente models (2024 update for universal GBS screening, or the original 2017 model), and after a well, equivocal, or ill clinical exam.",
  "category": "health",
  "subcategory": "clinical",
  "url": "https://www.acalculator.org/health/kaiser-sepsis-calculator",
  "markdown": "https://www.acalculator.org/health/kaiser-sepsis-calculator.md",
  "kind": "function",
  "method": "Risk at birth = 1 ÷ (1 + e^−x), x = intercept + b1 × temperature (°F) + b2 × GA + b3 × GA² + b4 × (ROM hours + 0.05)^0.2 + b5 × (GBS prophylaxis ≥ 2 h or broad-spectrum 2 to 3.9 h) + b6 × (broad-spectrum ≥ 4 h) + b7 × GBS positive + b8 × GBS unknown. 2024 model: 0.85194656, −7.72247124, 0.09842383, 0.86770862, −2.13142945, −2.33985917, 1.02265353, 1.13710111, exam LRs 0.36, 3.65, 14.5. 2017 model: 0.868, −6.9325, 0.0877, 1.2256, −1.0488, −1.1861, 0.5771, 0.0427, exam LRs 0.41, 5, 21.2. After the exam: odds × LR.",
  "assumptions": [
    "The 2024 model is for babies born at 35 weeks or later where GBS screening is universal; the 2017 model is for 34 weeks or later where it is not (Kaiser 2024 model FAQ).",
    "Risks are per 1,000 live births, rounded to 2 decimals, halves up.",
    "The page shows risk only. It does not show the care recommendations of the Kaiser tool."
  ],
  "inputs": {
    "$schema": "https://json-schema.org/draft/2020-12/schema",
    "type": "object",
    "properties": {
      "model": {
        "title": "Kaiser model",
        "description": "Kaiser suggests the 2024 model where pregnant people have universal GBS screening, as in the US, and the original 2017 model where they do not.",
        "type": "string",
        "enum": [
          "2024",
          "2017"
        ]
      },
      "inc": {
        "title": "EOS incidence (per 1,000 births)",
        "description": "The rate of early-onset sepsis where the baby is born. 0.5 is the US national rate the tool names.",
        "type": "string",
        "enum": [
          "1",
          "2",
          "4",
          "0.1",
          "0.2",
          "0.3",
          "0.4",
          "0.5",
          "0.6",
          "0.7",
          "0.8",
          "0.9"
        ]
      },
      "wk": {
        "title": "Gestational age: weeks",
        "description": "Completed weeks of gestation at birth: 35 to 43 for the 2024 model, 34 to 43 for the 2017 model.",
        "type": "integer",
        "minimum": 34,
        "maximum": 43
      },
      "d": {
        "title": "and days",
        "description": "Extra days past the completed weeks, 0 to 6.",
        "type": "integer",
        "minimum": 0,
        "maximum": 6
      },
      "t": {
        "title": "Highest maternal temperature",
        "description": "The mother’s highest temperature in labor, before the birth.",
        "type": [
          "number",
          "string"
        ],
        "x-quantity": "temperature",
        "minimum": 308.15,
        "maximum": 315.15
      },
      "rom": {
        "title": "Rupture of membranes (hours)",
        "description": "Hours from when the waters broke to the birth, 0 to 240.",
        "type": "number",
        "minimum": 0,
        "maximum": 240
      },
      "gbs": {
        "title": "Mother’s GBS status",
        "description": "The group B streptococcus (GBS) test result in pregnancy.",
        "type": "string",
        "enum": [
          "negative",
          "positive",
          "unknown"
        ]
      },
      "abx": {
        "title": "Antibiotics in labor",
        "description": "The type of antibiotics given to the mother in labor, and how long before the birth. In the 2024 model only ampicillin, penicillin, or cefazolin count as GBS prophylaxis.",
        "type": "string",
        "enum": [
          "broad4",
          "broad2",
          "gbs2",
          "none"
        ]
      }
    }
  },
  "outputs": {
    "atBirth": {
      "label": "Risk at birth",
      "description": "EOS risk per 1,000 births from the maternal factors, to 2 decimals.",
      "format": "number"
    },
    "well": {
      "label": "If the baby appears well",
      "description": "EOS risk per 1,000 births after a well-appearing exam, to 2 decimals.",
      "format": "number"
    },
    "equivocal": {
      "label": "If the exam is equivocal",
      "description": "EOS risk per 1,000 births after an equivocal exam, to 2 decimals.",
      "format": "number"
    },
    "ill": {
      "label": "If the baby shows clinical illness",
      "description": "EOS risk per 1,000 births after an exam showing clinical illness, to 2 decimals.",
      "format": "number"
    }
  },
  "defaultAnswer": {
    "inputs": {
      "model": "2024",
      "inc": "0.5",
      "d": 0,
      "gbs": "negative",
      "abx": "none",
      "wk": 40,
      "t": 310.15,
      "rom": 10
    },
    "outputs": {
      "atBirth": 0.29,
      "well": 0.1,
      "equivocal": 1.05,
      "ill": 4.17
    },
    "text": "The early-onset sepsis risk at birth is 0.29 per 1,000 births (0.1 per 1,000 if the baby appears well)."
  },
  "examples": [
    {
      "given": {
        "model": "2024",
        "inc": "0.5",
        "wk": 40,
        "d": 0,
        "t": 310.15,
        "rom": 10,
        "gbs": "negative",
        "abx": "none"
      },
      "expect": {
        "atBirth": 0.29,
        "well": 0.1,
        "equivocal": 1.05,
        "ill": 4.17
      },
      "source": "Kaiser 2024 model FAQ: intercept 57.29929499 − ln[(0.9995 ÷ 0.0005) × (0.0002763 ÷ 0.9997237)] = 57.8926; x = −8.1496, 0.2888 per 1,000; LRs 0.36, 3.65, 14.5 (hand calculation in content.mdx, Python 3)"
    },
    {
      "given": {
        "model": "2024",
        "inc": "0.5",
        "wk": 39,
        "d": 3,
        "t": 311.7611111111112,
        "rom": 20,
        "gbs": "positive",
        "abx": "gbs2"
      },
      "expect": {
        "atBirth": 1.31,
        "well": 0.47,
        "equivocal": 4.76,
        "ill": 18.63
      },
      "source": "Kaiser 2024 model: 39 weeks 3 days, 101.5 °F, 20 hours, GBS positive, GBS prophylaxis: x = −6.6382, 1.3077 per 1,000 (Python 3)"
    },
    {
      "given": {
        "model": "2024",
        "inc": "0.3",
        "wk": 37,
        "d": 0,
        "t": 311.0388888888889,
        "rom": 30,
        "gbs": "unknown",
        "abx": "broad4"
      },
      "expect": {
        "atBirth": 0.44,
        "well": 0.16,
        "equivocal": 1.6,
        "ill": 6.32
      },
      "source": "Kaiser 2024 model, 0.3 per 1,000 (intercept 57.3816, the FAQ table gives 57.4): x = −7.7316, 0.4386 per 1,000 (Python 3)"
    },
    {
      "given": {
        "model": "2017",
        "inc": "0.5",
        "wk": 40,
        "d": 0,
        "t": 310.15,
        "rom": 10,
        "gbs": "negative",
        "abx": "none"
      },
      "expect": {
        "atBirth": 0.14,
        "well": 0.06,
        "equivocal": 0.69,
        "ill": 2.93
      },
      "source": "Puopolo 2011 model with the coefficients in Nguyen 2024 (Cureus) and the Kaiser 0.5 per 1,000 intercept 40.5656: 0.1384 per 1,000; exam LRs 0.41, 5, 21.2 (hand calculation in content.mdx, Python 3)"
    },
    {
      "given": {
        "model": "2017",
        "inc": "0.5",
        "wk": 39,
        "d": 3,
        "t": 311.7611111111112,
        "rom": 20,
        "gbs": "positive",
        "abx": "gbs2"
      },
      "expect": {
        "atBirth": 1.4,
        "well": 0.57,
        "equivocal": 6.95,
        "ill": 28.84
      },
      "source": "Same model: 39 weeks 3 days, 101.5 °F, 20 hours, GBS positive, GBS-specific antibiotics: 1.3987 per 1,000 (hand calculation)"
    },
    {
      "given": {
        "model": "2017",
        "inc": "0.3",
        "wk": 35,
        "d": 0,
        "t": 311.0388888888889,
        "rom": 30,
        "gbs": "unknown",
        "abx": "broad4"
      },
      "expect": {
        "atBirth": 1.01,
        "well": 0.41,
        "equivocal": 5.01,
        "ill": 20.89
      },
      "source": "Same model, 0.3 per 1,000 intercept 40.0528: 1.0053 per 1,000 (hand calculation in content.mdx)"
    },
    {
      "given": {
        "model": "2017",
        "inc": "0.6",
        "wk": 41,
        "d": 2,
        "t": 311.65,
        "rom": 5,
        "gbs": "negative",
        "abx": "none"
      },
      "expect": {
        "atBirth": 1.73,
        "well": 0.71,
        "equivocal": 8.61,
        "ill": 35.5
      },
      "source": "Same model, 0.6 per 1,000 intercept 40.7489: 1.7333 per 1,000 (hand calculation in content.mdx)"
    }
  ],
  "sources": [
    "Puopolo KM, Draper D, Wi S, et al. Estimating the probability of neonatal early-onset infection on the basis of maternal risk factors. Pediatrics. 2011;128(5):e1155-e1163. https://doi.org/10.1542/peds.2010-3464",
    "Escobar GJ, Puopolo KM, Wi S, et al. Stratification of risk of early-onset sepsis in newborns ≥34 weeks’ gestation. Pediatrics. 2014;133(1):30-36. https://doi.org/10.1542/peds.2013-1689",
    "Kuzniewicz MW, Puopolo KM, Fischer A, et al. A quantitative, risk-based approach to the management of neonatal early-onset sepsis. JAMA Pediatr. 2017;171(4):365-371. https://doi.org/10.1001/jamapediatrics.2016.4678",
    "Kuzniewicz MW, Escobar GJ, Forquer H, et al. Update to the Neonatal Early-Onset Sepsis Calculator utilizing a contemporary cohort. Pediatrics. 2024;154(4):e2023065267. https://doi.org/10.1542/peds.2023-065267",
    "Nguyen TT, Nguyen OTH, Duong MN, Giang LTP. Antibiotic management for early-onset sepsis in neonates with gestational ages of ≥34 weeks: the Kaiser sepsis calculator. Cureus. 2024;16(7):e63704, Appendix (model coefficients and likelihood ratios). https://doi.org/10.7759/cureus.63704",
    "Kaiser Permanente Division of Research. Neonatal Early-Onset Sepsis Calculator, original (2017) model, incidence options and intercepts. https://neonatalsepsiscalculator.kaiserpermanente.org/ (retrieved 2026-09-29)",
    "Kaiser Permanente Division of Research. Neonatal Early-Onset Sepsis Calculator, FAQ 2024 EOS Calculator Model Update (coefficients, intercept formula and table, likelihood ratios, which model to use). https://neonatalsepsiscalculator.kaiserpermanente.org/ModelUpdateFAQ.aspx (retrieved 2026-09-30)",
    "Kaiser Permanente Division of Research. Neonatal Early-Onset Sepsis Calculator, EMR implementation FAQ (the equation, the transformed rupture of membranes term, and the likelihood ratios). https://neonatalsepsiscalculator.kaiserpermanente.org/EmrFAQ.aspx (retrieved 2026-09-30)"
  ],
  "related": [],
  "changelog": [
    {
      "date": "2026-09-30",
      "note": "Adds the Kaiser 2024 model (the default, for settings with universal GBS screening, as in the US); the original 2017 model stays as an option."
    },
    {
      "date": "2026-09-30",
      "note": "Published after this site's editorial review against the cited sources (no clinician review); the page notices say so. The page now says where Kaiser suggests the 2024 model instead."
    }
  ]
}