VIRSTA score

VIRSTA

Sum the Tubiana 2016 VIRSTA items from caller-assigned Staphylococcus aureus bacteremia flags and CRP, and return high_risk when the total is 3 or more.

LIVE $0.005 USDC GET /api/calc/virsta

Markdown: /docs/virsta.md · Canonical: https://magentlab.com/docs/virsta

Not a medical device. Not a diagnosis, dose, or listing recommendation.

What it computes

Sum the Tubiana 2016 VIRSTA items from caller-assigned Staphylococcus aureus bacteremia flags and CRP, and return high_risk when the total is 3 or more.

When to use

When an agent has already assigned the Tubiana 2016 VIRSTA flags and a CRP in mg/L for Staphylococcus aureus bacteremia and needs the published 0-30 total and ≥3 high_risk flag, not a Duke classification, PREDICT/POSITIVE score, or an endocarditis diagnosis. magent does not examine the patient or assay CRP.

When not to use

Not a medical device and not a diagnosis or treatment recommendation. magent does not diagnose infective endocarditis.
Nine clinical flags are caller-assigned. magent does not examine the patient, interpret cultures, or assay CRP.
Permanent intracardiac device or previous IE is one Tubiana 2016 item (4 points if either is present). The two are not added separately.
CRP scores 1 only when crp_mg_l is above 190 mg/L (Tubiana 2016: above 190 mg/L). Exactly 190 scores 0. Range 0-500.
high_risk is true iff score ≥ 3 (paper: ≤2 low IE-risk, ≥3 higher risk / echocardiography priority). magent does not invent extra strata and does not order TTE or TEE. Not the modified Duke criteria.

Formula

VIRSTA = cerebral_or_peripheral_emboli (5 if present) + meningitis (5) + intracardiac_device_or_previous_ie (4) + iv_drug_use (4) + native_valve_disease (3) + persistent_bacteremia (3) + vertebral_osteomyelitis (2) + community_or_non_nosocomial (2) + severe_sepsis_or_shock (1) + (crp_mg_l > 190 → 1); Tubiana 2016 caller-assigned items; CRP cutoff is above 190 mg/L (not ≥190); intracardiac device or previous IE is one 4-point item; max 30; high_risk iff score ≥ 3

Citation

Title: The VIRSTA score, a prediction score to estimate risk of infective endocarditis and determine priority for echocardiography in patients with Staphylococcus aureus bacteremia
Authors: Tubiana S, Duval X, Alla F, Selton-Suty C, Tattevin P, Delahaye F, Piroth L, Chirouze C, Lavigne JP, Erpelding ML, Hoen B, Vandenesch F, Iung B, Le Moing V
Source: J Infect. 2016;72(5):544-553
DOI: 10.1016/j.jinf.2016.02.003

Worked example

All flags absent, CRP below cutoff

Given: cerebral_or_peripheral_emboli=falsecommunity_or_non_nosocomial=falsecrp_mg_l=50intracardiac_device_or_previous_ie=falseiv_drug_use=falsemeningitis=falsenative_valve_disease=falsepersistent_bacteremia=falsesevere_sepsis_or_shock=falsevertebral_osteomyelitis=false

All nine flags false → 0; CRP 50 mg/L is not above 190 → 0
Score = 0 (max 30); high_risk false

Native valve disease only (published ≥3 cutoff)

Given: cerebral_or_peripheral_emboli=falsecommunity_or_non_nosocomial=falsecrp_mg_l=50intracardiac_device_or_previous_ie=falseiv_drug_use=falsemeningitis=falsenative_valve_disease=truepersistent_bacteremia=falsesevere_sepsis_or_shock=falsevertebral_osteomyelitis=false

native_valve_disease true → 3; remaining flags false → 0; CRP 50 → 0
Score = 3 (max 30); high_risk true (threshold is ≥3)

All items present

Given: cerebral_or_peripheral_emboli=truecommunity_or_non_nosocomial=truecrp_mg_l=250intracardiac_device_or_previous_ie=trueiv_drug_use=truemeningitis=truenative_valve_disease=truepersistent_bacteremia=truesevere_sepsis_or_shock=truevertebral_osteomyelitis=true

5+5+4+4+3+3+2+2+1 + CRP 250 > 190 → 1
Score = 30 (max 30); high_risk true

Also searched as

VIRSTA score
Tubiana VIRSTA
S aureus bacteremia endocarditis score
Staphylococcus aureus bacteremia IE score
VIRSTA echocardiography priority
infective endocarditis SAB score

Try

Opens the live endpoint. Unpaid browser requests show the paywall; agents should send Accept: application/json.

/api/calc/virsta?cerebral_or_peripheral_emboli=false&meningitis=false&intracardiac_device_or_previous_ie=false&iv_drug_use=false&native_valve_disease=false&persistent_bacteremia=false&vertebral_osteomyelitis=false&community_or_non_nosocomial=false&severe_sepsis_or_shock=false&crp_mg_l=50

Full URL: https://api.magentlab.com/api/calc/virsta?cerebral_or_peripheral_emboli=false&meningitis=false&intracardiac_device_or_previous_ie=false&iv_drug_use=false&native_valve_disease=false&persistent_bacteremia=false&vertebral_osteomyelitis=false&community_or_non_nosocomial=false&severe_sepsis_or_shock=false&crp_mg_l=50

Call

Expect HTTP 402 until you retry with PAYMENT-SIGNATURE. Incomplete query params return HTTP 400 before any quote or charge.

curl -i -H "Accept: application/json" "https://api.magentlab.com/api/calc/virsta?cerebral_or_peripheral_emboli=false&meningitis=false&intracardiac_device_or_previous_ie=false&iv_drug_use=false&native_valve_disease=false&persistent_bacteremia=false&vertebral_osteomyelitis=false&community_or_non_nosocomial=false&severe_sepsis_or_shock=false&crp_mg_l=50"

Parameters

Name	Type	Required	Description
`cerebral_or_peripheral_emboli`	boolean	required	Caller-assigned cerebral or peripheral (extracerebral) emboli (Tubiana 2016). true scores 5. magent does not diagnose emboli or endocarditis.
`meningitis`	boolean	required	Caller-assigned meningitis (Tubiana 2016). true scores 5. magent does not diagnose meningitis or endocarditis.
`intracardiac_device_or_previous_ie`	boolean	required	Permanent intracardiac device or previous infective endocarditis as one Tubiana 2016 item. true scores 4 if either is present; the two are not added separately. magent does not diagnose IE.
`iv_drug_use`	boolean	required	Caller-assigned intravenous drug use (Tubiana 2016). true scores 4. magent does not take a social history.
`native_valve_disease`	boolean	required	Caller-assigned preexisting native valve disease (Tubiana 2016). true scores 3. magent does not diagnose valve disease.
`persistent_bacteremia`	boolean	required	H48-persistent bacteremia (positive blood culture after 48 hours) as assigned by the caller (Tubiana 2016). true scores 3. magent does not interpret cultures.
`vertebral_osteomyelitis`	boolean	required	Caller-assigned vertebral osteomyelitis / spondylodiscitis (Tubiana 2016). true scores 2. magent does not diagnose osteomyelitis.
`community_or_non_nosocomial`	boolean	required	Community-acquired or non-nosocomial healthcare-associated Staphylococcus aureus bacteremia (Tubiana 2016), as assigned by the caller. true scores 2; nosocomial is false (0). magent does not classify acquisition.
`severe_sepsis_or_shock`	boolean	required	Caller-assigned severe sepsis or septic shock (Tubiana 2016). true scores 1. magent does not diagnose sepsis.
`crp_mg_l`	number	required	C-reactive protein in mg/L (0-500). Tubiana 2016 scores 1 if CRP is above 190 mg/L (not ≥190). magent does not assay CRP.

Bulk (POST)

POST the same path with a JSON items array. The first item is the GET unit; each additional item is $0.002. Invalid items return HTTP 400 before settlement.

POST /api/calc/virsta Max 25 unit_amount + extra_item_amount * (n - 1) extra $0.002 PREVIEW

1 to 25 items. Each item uses the same keys as the GET query parameters.
POST of 1 item costs the same as GET. Lists longer than 25: chunk into multiple POSTs. Extra items still execute; do not pad dummy rows.
The first invalid item fails the whole request (index in the 400 JSON). You are not charged.
HTTP 200 is {count, path, items}. Each items[i] is the GET 200 body for that row.
Catalog misses (empty matches, found=false) stay paid 200s inside that slot.
x402 resource URL is this path plus n and body_sha256. Browsers that prefer text/html get the same paywall as GET; Pay retries POST with the same items.

Example request (fixture)

{
  "items": [
    {
      "cerebral_or_peripheral_emboli": "false",
      "community_or_non_nosocomial": "false",
      "crp_mg_l": "50",
      "intracardiac_device_or_previous_ie": "false",
      "iv_drug_use": "false",
      "meningitis": "false",
      "native_valve_disease": "false",
      "persistent_bacteremia": "false",
      "severe_sepsis_or_shock": "false",
      "vertebral_osteomyelitis": "false"
    },
    {
      "cerebral_or_peripheral_emboli": "false",
      "community_or_non_nosocomial": "false",
      "crp_mg_l": "50",
      "intracardiac_device_or_previous_ie": "false",
      "iv_drug_use": "false",
      "meningitis": "false",
      "native_valve_disease": "false",
      "persistent_bacteremia": "false",
      "severe_sepsis_or_shock": "false",
      "vertebral_osteomyelitis": "false"
    }
  ]
}

Open bulk paywall →

Opens a two-item fixture on the API host. Unpaid browsers get the same MetaMask paywall as GET; Pay retries POST with those items.

Example 200 (fixture)

{
  "count": 2,
  "path": "/api/calc/virsta",
  "items": [
    {
      "components": [
        {
          "factor": "cerebral_or_peripheral_emboli",
          "points": 0,
          "present": false
        },
        {
          "factor": "meningitis",
          "points": 0,
          "present": false
        },
        {
          "factor": "intracardiac_device_or_previous_ie",
          "points": 0,
          "present": false
        },
        {
          "factor": "iv_drug_use",
          "points": 0,
          "present": false
        },
        {
          "factor": "native_valve_disease",
          "points": 0,
          "present": false
        },
        {
          "factor": "persistent_bacteremia",
          "points": 0,
          "present": false
        },
        {
          "factor": "vertebral_osteomyelitis",
          "points": 0,
          "present": false
        },
        {
          "factor": "community_or_non_nosocomial",
          "points": 0,
          "present": false
        },
        {
          "factor": "severe_sepsis_or_shock",
          "points": 0,
          "present": false
        },
        {
          "value": 50.0,
          "factor": "crp_gt_190",
          "points": 0,
          "present": false
        }
      ],
      "disclaimer": "Not a medical device. Deterministic published-formula or published-code output for autonomous agents. A licensed clinician remains responsible for patient care and billing submissions.",
      "citation": {
        "authors": "Tubiana S, Duval X, Alla F, Selton-Suty C, Tattevin P, Delahaye F, Piroth L, Chirouze C, Lavigne JP, Erpelding ML, Hoen B, Vandenesch F, Iung B, Le Moing V",
        "doi": "10.1016/j.jinf.2016.02.003",
        "id": "tubiana-2016",
        "pmid": "26916042",
        "source": "J Infect. 2016;72(5):544-553",
        "title": "The VIRSTA score, a prediction score to estimate risk of infective endocarditis and determine priority for echocardiography in patients with Staphylococcus aureus bacteremia"
      },
      "formula": "virsta",
      "formula_expression": "VIRSTA = cerebral_or_peripheral_emboli (5 if present) + meningitis (5) + intracardiac_device_or_previous_ie (4) + iv_drug_use (4) + native_valve_disease (3) + persistent_bacteremia (3) + vertebral_osteomyelitis (2) + community_or_non_nosocomial (2) + severe_sepsis_or_shock (1) + (crp_mg_l > 190 → 1); Tubiana 2016 caller-assigned items; CRP cutoff is above 190 mg/L (not ≥190); intracardiac device or previous IE is one 4-point item; max 30; high_risk iff score ≥ 3",
      "max_score": 30,
      "score": 0,
      "high_risk": false,
      "crp_mg_l": 50.0
    },
    {
      "components": [
        {
          "factor": "cerebral_or_peripheral_emboli",
          "points": 0,
          "present": false
        },
        {
          "factor": "meningitis",
          "points": 0,
          "present": false
        },
        {
          "factor": "intracardiac_device_or_previous_ie",
          "points": 0,
          "present": false
        },
        {
          "factor": "iv_drug_use",
          "points": 0,
          "present": false
        },
        {
          "factor": "native_valve_disease",
          "points": 0,
          "present": false
        },
        {
          "factor": "persistent_bacteremia",
          "points": 0,
          "present": false
        },
        {
          "factor": "vertebral_osteomyelitis",
          "points": 0,
          "present": false
        },
        {
          "factor": "community_or_non_nosocomial",
          "points": 0,
          "present": false
        },
        {
          "factor": "severe_sepsis_or_shock",
          "points": 0,
          "present": false
        },
        {
          "value": 50.0,
          "factor": "crp_gt_190",
          "points": 0,
          "present": false
        }
      ],
      "disclaimer": "Not a medical device. Deterministic published-formula or published-code output for autonomous agents. A licensed clinician remains responsible for patient care and billing submissions.",
      "citation": {
        "authors": "Tubiana S, Duval X, Alla F, Selton-Suty C, Tattevin P, Delahaye F, Piroth L, Chirouze C, Lavigne JP, Erpelding ML, Hoen B, Vandenesch F, Iung B, Le Moing V",
        "doi": "10.1016/j.jinf.2016.02.003",
        "id": "tubiana-2016",
        "pmid": "26916042",
        "source": "J Infect. 2016;72(5):544-553",
        "title": "The VIRSTA score, a prediction score to estimate risk of infective endocarditis and determine priority for echocardiography in patients with Staphylococcus aureus bacteremia"
      },
      "formula": "virsta",
      "formula_expression": "VIRSTA = cerebral_or_peripheral_emboli (5 if present) + meningitis (5) + intracardiac_device_or_previous_ie (4) + iv_drug_use (4) + native_valve_disease (3) + persistent_bacteremia (3) + vertebral_osteomyelitis (2) + community_or_non_nosocomial (2) + severe_sepsis_or_shock (1) + (crp_mg_l > 190 → 1); Tubiana 2016 caller-assigned items; CRP cutoff is above 190 mg/L (not ≥190); intracardiac device or previous IE is one 4-point item; max 30; high_risk iff score ≥ 3",
      "max_score": 30,
      "score": 0,
      "high_risk": false,
      "crp_mg_l": 50.0
    }
  ]
}

Response

Field	Type	Description
`formula`	string	virsta
`formula_expression`	string	Exact expression used
`score`	integer	VIRSTA points 0-30
`max_score`	integer	Always 30
`high_risk`	boolean	true iff score ≥ 3 (Tubiana 2016 not-low-risk / echocardiography-priority cutoff). Not a diagnosis and not an imaging order. No extra strata.
`crp_mg_l`	number	CRP in mg/L used
`components`	array	Per-item Tubiana 2016 points
`citation`	object	Tubiana J Infect 2016 citation
`disclaimer`	string	Not-a-device notice

Example JSON

Machine form of the same example. Frozen fixture. Not a live lookup.

{
  "components": [
    {
      "factor": "cerebral_or_peripheral_emboli",
      "points": 0,
      "present": false
    },
    {
      "factor": "meningitis",
      "points": 0,
      "present": false
    },
    {
      "factor": "intracardiac_device_or_previous_ie",
      "points": 0,
      "present": false
    },
    {
      "factor": "iv_drug_use",
      "points": 0,
      "present": false
    },
    {
      "factor": "native_valve_disease",
      "points": 0,
      "present": false
    },
    {
      "factor": "persistent_bacteremia",
      "points": 0,
      "present": false
    },
    {
      "factor": "vertebral_osteomyelitis",
      "points": 0,
      "present": false
    },
    {
      "factor": "community_or_non_nosocomial",
      "points": 0,
      "present": false
    },
    {
      "factor": "severe_sepsis_or_shock",
      "points": 0,
      "present": false
    },
    {
      "value": 50.0,
      "factor": "crp_gt_190",
      "points": 0,
      "present": false
    }
  ],
  "disclaimer": "Not a medical device. Deterministic published-formula or published-code output for autonomous agents. A licensed clinician remains responsible for patient care and billing submissions.",
  "citation": {
    "authors": "Tubiana S, Duval X, Alla F, Selton-Suty C, Tattevin P, Delahaye F, Piroth L, Chirouze C, Lavigne JP, Erpelding ML, Hoen B, Vandenesch F, Iung B, Le Moing V",
    "doi": "10.1016/j.jinf.2016.02.003",
    "id": "tubiana-2016",
    "pmid": "26916042",
    "source": "J Infect. 2016;72(5):544-553",
    "title": "The VIRSTA score, a prediction score to estimate risk of infective endocarditis and determine priority for echocardiography in patients with Staphylococcus aureus bacteremia"
  },
  "formula": "virsta",
  "formula_expression": "VIRSTA = cerebral_or_peripheral_emboli (5 if present) + meningitis (5) + intracardiac_device_or_previous_ie (4) + iv_drug_use (4) + native_valve_disease (3) + persistent_bacteremia (3) + vertebral_osteomyelitis (2) + community_or_non_nosocomial (2) + severe_sepsis_or_shock (1) + (crp_mg_l > 190 → 1); Tubiana 2016 caller-assigned items; CRP cutoff is above 190 mg/L (not ≥190); intracardiac device or previous IE is one 4-point item; max 30; high_risk iff score ≥ 3",
  "max_score": 30,
  "score": 0,
  "high_risk": false,
  "crp_mg_l": 50.0
}

Client errors (HTTP 400)

Invalid params return 400 without charge. Shared HTTP 402 and 503 meanings: Payments.

HTTP	Code	When
400	`invalid_virsta`	VIRSTA needs Tubiana 2016 Staphylococcus aureus bacteremia flags and CRP in published ranges. Returned before settlement; you are not charged.
400	`invalid_items`	POST body must be a JSON object with only an items array Returned before settlement; you are not charged.
400	`invalid_item_count`	items must be an array of 1 to 25 objects Returned before settlement; you are not charged.
400	`invalid_item`	each items entry must be a JSON object Returned before settlement; you are not charged.

Related tools

Duke — Apply the Durack 1994 original Duke criteria for infective endocarditis and return definite, possible, or rejected from caller-assigned pathologic, major, minor, and rejected flags.
IE mortality — Compute the Park 2016 ICE simplified risk score for 6-month mortality in infective endocarditis from age and caller-assigned Table 5 flags, and return the score, quadratic 6-month mortality percent, and whether score >= 8.

Payment

Unpaid requests return HTTP 402 even if query parameters or POST items are missing or invalid, so CDP and agents can index the path. After a PAYMENT-SIGNATURE, invalid params return HTTP 400 JSON before settlement. magent does not charge. Fix the params, then request a new 402 quote for that complete URL. Catalog misses (empty matches, found=false) are valid paid 200s. Unpaid valid requests return HTTP 402 with a base64 PAYMENT-REQUIRED header. HTTP 503 is not a new quote: retry the same PAYMENT-SIGNATURE. Full handshake and shared payment errors: Payments. Stdio MCP: /docs/mcp.

Guarantees

HTTP 402 is unpaid, including a missing query. After PAYMENT-SIGNATURE, invalid parameters return HTTP 400 before settlement. You are not charged. HTTP 402 never includes the tool JSON.
exact: settlement finishes before the tool (paymentFlow upfront). batch-settlement: verify/deposit before the tool; chargedCumulativeAmount commits after HTTP 2xx. Uncertain or failed settlement fails closed (HTTP 503). Retry the same PAYMENT-SIGNATURE.
HTTP 402 is unpaid only. Do not sign a second authorization because of a 503.
Execution is timeout-bounded and concurrency-capped.
Calculator inputs are stored encrypted for allowlisted operators (Magent Console). They are not in public logs, SSH lookups, catalog, or rollups. Request logs store path without query.