Lab Fishbone API: JSON to PNG, SVG or Text

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Request body

Field	Type	Description
title	string	Heading shown top-left at 22px bold, e.g. "Day 3 labs". An empty string hides it. Never put a patient name or identifier here: links carry the chart itself. max 140 chars · default "Labs"
panelsrequired	object[]	The panels to draw (1–8), in order, two or three per row. Each has a `type` and its values as flat string keys; leave a key out to leave its position blank. More than 8 are dropped. max 8 items
flag	boolean	Flag numeric values outside the adult reference range: red with ↑ when high, blue with ↓ when low. Default true. Manual `flags` on a panel apply either way. Ranges vary by lab; this is a drawing aid, not clinical decision support. default true
units	string	Which reference ranges the automatic flags use: "US" (conventional units: mg/dL, g/dL, %, mmHg; the default) or "SI" (mmol/L, µmol/L, g/L, L/L, kPa). It does not convert values. "US", "SI" · default "US"
labels	boolean	Show a small analyte name (Na, K, Hgb…) beside every value. Default false: experienced readers know the positions; turn it on for teaching or for readers new to the shorthand. default false
width	integer	Chart width in pixels (640–2400). Omit it (recommended) and the chart sizes itself to its content with comfortable margins, between 880 and 1280px wide. PNG output renders at 2x. 640–2400
palette	string[]	Hex colours; only the first is used, for the small panel-type tags. The skeletons stay monochrome, and flags are always red (high) and blue (low). max 12 items · default ["#4f46e5","#0ea5e9","#10b981","#f59e0b","#ef4444","#6b7280"]

panels[] item

Field	Type	Description
type	string	Which skeleton to draw, and which value keys it reads: "bmp" (basic metabolic panel / Chem-7: na, cl, bun over k, hco3, cr, with glu in the tail), "cbc" (wbc > hgb over hct < plt), "coag" (pt \| ptt over inr), "lft" (hepatic panel: tp, ast, tbili over alb, alt, alp), "abg" (ph / pco2 / po2 / hco3) or "chem" (extended electrolytes: ca over mg \| phos). Default "bmp". Keys that belong to another type are ignored with a warning. "bmp", "cbc", "coag", "lft", "abg", "chem" · default "bmp"
caption	string	Optional short caption above the panel, after its type tag, e.g. "06:00" or "Day 3, post-op". Never a patient name or identifier. max 40 chars
na	string	Sodium (Na), BMP: top left. mmol/L, e.g. "138". A string of up to 8 characters; non-numeric text such as "<0.1", "pending" or "—" is shown as written and never flagged. Omit it to leave the position blank. max 8 chars
k	string	Potassium (K), BMP: bottom left. mmol/L, e.g. "4.1". A string of up to 8 characters; non-numeric text such as "<0.1", "pending" or "—" is shown as written and never flagged. Omit it to leave the position blank. max 8 chars
cl	string	Chloride (Cl), BMP: top middle. mmol/L, e.g. "102". A string of up to 8 characters; non-numeric text such as "<0.1", "pending" or "—" is shown as written and never flagged. Omit it to leave the position blank. max 8 chars
hco3	string	Bicarbonate (HCO3): BMP bottom middle (serum CO2, mmol/L, e.g. "24"), or the last value of an ABG. A string of up to 8 characters; non-numeric text such as "<0.1", "pending" or "—" is shown as written and never flagged. Omit it to leave the position blank. max 8 chars
bun	string	Blood urea nitrogen (BUN), BMP: top right. mg/dL (US) or urea mmol/L (SI), e.g. "18". A string of up to 8 characters; non-numeric text such as "<0.1", "pending" or "—" is shown as written and never flagged. Omit it to leave the position blank. max 8 chars
cr	string	Creatinine (Cr), BMP: bottom right. mg/dL (US) or µmol/L (SI), e.g. "1.1". A string of up to 8 characters; non-numeric text such as "<0.1", "pending" or "—" is shown as written and never flagged. Omit it to leave the position blank. max 8 chars
glu	string	Glucose (Glu), BMP: in the tail on the right. mg/dL (US) or mmol/L (SI), e.g. "112". A string of up to 8 characters; non-numeric text such as "<0.1", "pending" or "—" is shown as written and never flagged. Omit it to leave the position blank. max 8 chars
wbc	string	White blood cells (WBC), CBC: left. ×10³/µL, e.g. "8.4". A string of up to 8 characters; non-numeric text such as "<0.1", "pending" or "—" is shown as written and never flagged. Omit it to leave the position blank. max 8 chars
hgb	string	Hemoglobin (Hgb), CBC: top middle. g/dL (US) or g/L (SI), e.g. "13.2". A string of up to 8 characters; non-numeric text such as "<0.1", "pending" or "—" is shown as written and never flagged. Omit it to leave the position blank. max 8 chars
hct	string	Hematocrit (Hct), CBC: bottom middle. % (US) or L/L (SI), e.g. "39.5". A string of up to 8 characters; non-numeric text such as "<0.1", "pending" or "—" is shown as written and never flagged. Omit it to leave the position blank. max 8 chars
plt	string	Platelets (Plt), CBC: right. ×10³/µL, e.g. "245". A string of up to 8 characters; non-numeric text such as "<0.1", "pending" or "—" is shown as written and never flagged. Omit it to leave the position blank. max 8 chars
pt	string	Prothrombin time (PT), coags: top left. Seconds, e.g. "12.8". A string of up to 8 characters; non-numeric text such as "<0.1", "pending" or "—" is shown as written and never flagged. Omit it to leave the position blank. max 8 chars
inr	string	INR, coags: below the line. e.g. "1.1". A string of up to 8 characters; non-numeric text such as "<0.1", "pending" or "—" is shown as written and never flagged. Omit it to leave the position blank. max 8 chars
ptt	string	Partial thromboplastin time (PTT/aPTT), coags: top right. Seconds, e.g. "31". A string of up to 8 characters; non-numeric text such as "<0.1", "pending" or "—" is shown as written and never flagged. Omit it to leave the position blank. max 8 chars
tp	string	Total protein (TP), LFT: top left. g/dL (US) or g/L (SI), e.g. "7.0". A string of up to 8 characters; non-numeric text such as "<0.1", "pending" or "—" is shown as written and never flagged. Omit it to leave the position blank. max 8 chars
alb	string	Albumin (Alb), LFT: bottom left. g/dL (US) or g/L (SI), e.g. "3.9". A string of up to 8 characters; non-numeric text such as "<0.1", "pending" or "—" is shown as written and never flagged. Omit it to leave the position blank. max 8 chars
ast	string	AST, LFT: top middle. U/L, e.g. "32". A string of up to 8 characters; non-numeric text such as "<0.1", "pending" or "—" is shown as written and never flagged. Omit it to leave the position blank. max 8 chars
alt	string	ALT, LFT: bottom middle. U/L, e.g. "28". A string of up to 8 characters; non-numeric text such as "<0.1", "pending" or "—" is shown as written and never flagged. Omit it to leave the position blank. max 8 chars
alp	string	Alkaline phosphatase (ALP), LFT: bottom right. U/L, e.g. "88". A string of up to 8 characters; non-numeric text such as "<0.1", "pending" or "—" is shown as written and never flagged. Omit it to leave the position blank. max 8 chars
tbili	string	Total bilirubin (T bili), LFT: top right. mg/dL (US) or µmol/L (SI), e.g. "0.8". A string of up to 8 characters; non-numeric text such as "<0.1", "pending" or "—" is shown as written and never flagged. Omit it to leave the position blank. max 8 chars
ph	string	pH, ABG: first. e.g. "7.38". A string of up to 8 characters; non-numeric text such as "<0.1", "pending" or "—" is shown as written and never flagged. Omit it to leave the position blank. max 8 chars
pco2	string	pCO2, ABG: second. mmHg (US) or kPa (SI), e.g. "40". A string of up to 8 characters; non-numeric text such as "<0.1", "pending" or "—" is shown as written and never flagged. Omit it to leave the position blank. max 8 chars
po2	string	pO2, ABG: third. mmHg (US) or kPa (SI), e.g. "92". A string of up to 8 characters; non-numeric text such as "<0.1", "pending" or "—" is shown as written and never flagged. Omit it to leave the position blank. max 8 chars
ca	string	Calcium (Ca), Ca/Mg/Phos: above the line. mg/dL (US) or mmol/L (SI), e.g. "9.2". A string of up to 8 characters; non-numeric text such as "<0.1", "pending" or "—" is shown as written and never flagged. Omit it to leave the position blank. max 8 chars
mg	string	Magnesium (Mg), Ca/Mg/Phos: bottom left. mg/dL (US) or mmol/L (SI), e.g. "2.0". A string of up to 8 characters; non-numeric text such as "<0.1", "pending" or "—" is shown as written and never flagged. Omit it to leave the position blank. max 8 chars
phos	string	Phosphate (Phos), Ca/Mg/Phos: bottom right. mg/dL (US) or mmol/L (SI), e.g. "3.4". A string of up to 8 characters; non-numeric text such as "<0.1", "pending" or "—" is shown as written and never flagged. Omit it to leave the position blank. max 8 chars
flags	object	Optional manual flags that override the automatic ones for single values: { "k": "high" } draws K in red with ↑, "low" in blue with ↓, "normal" removes an automatic flag. Keys are the value keys above.

Endpoints

POST /api/render/labfishbone returns image/png; add ?format=svg for SVG.
GET /labfishbone.png?d=<payload> and /labfishbone.svg?d=<payload> render a chart from a link. The payload is the JSON body, raw-deflated and base64url-encoded. Nothing is stored: links are permanent and cached for a year.
/labfishbone#d=<payload> opens the same chart in the builder for editing.
GET /api/render/labfishbone?demo=1 returns the demo chart.
GET /api/schema/labfishbone returns the JSON Schema, for code generators and AIs.

Errors and adjustments

Input is lenient where the intent is clear: numeric strings become numbers, out-of-range values are clamped, and unknown fields are ignored. Adjustments are listed in the X-Render-Warnings header. Anything unclear returns a 400 that says how to fix it:

{
  "error": "Invalid payload",
  "issues": [{ "path": "tasks", "message": "must be an array" }],
  "example": { … }
}

Calling from an AI assistant?

Use the hosted MCP server instead. It gives Claude, Cursor and other MCP clients a create_lab_fishbone tool that returns the image plus image, SVG and edit links. See the MCP page →