# qPCR Relative Expression Calculator (Pfaffl Method)

> qPCR Relative Expression Calculator (Pfaffl Method) is a paid API for AI agents from www.mahastrategies.com, paid per call via x402, $0.058001/call, status unknown (last checked 2026-10-13).

Calculates Pfaffl relative expression ratios from supplied Ct values and amplification efficiencies for target and reference genes, requiring a declared stable reference gene.

## Facts

- Endpoint: POST https://www.mahastrategies.com/api/v1/micro/biology-qpcr-relative-expression?utm_source=zero.xyz
- Price: $0.058001/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-13
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/qpcr-relative-expression-calculator-pfaffl-method-2c229b94
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_IpwzbRrsjglZ0tx9kNvWN

Status and success rate cover calls made through Zero and Zero's own probes. Third-party monitors may report differently.

## How to call it through Zero

Zero handles the 402 payment challenge and records the run. With the Zero CLI installed (`npm i -g @zeroxyz/cli`):

```sh
zero fetch --capability qpcr-relative-expression-calculator-pfaffl-method-2c229b94 -d '<json body>'
```

Example prompt: Calculate the Pfaffl relative expression ratio for my qPCR data: target sample Ct is 22.4, target control Ct is 25.1, reference sample Ct is 18.6, reference control Ct is 18.9, target efficiency is 1.95, reference efficiency is 1.98, and I confirm the reference gene is stable. Data class is synthetic.

## When to prefer this

Choose this endpoint when you need a mathematically rigorous Pfaffl-corrected relative expression ratio that accounts for actual PCR amplification efficiencies rather than assuming 100% efficiency (as in the standard ΔΔCt method). Ideal when primer efficiencies differ between target and reference genes, or when high accuracy is required in quantitative expression analysis. Not suitable if you need diagnostic interpretation, absolute quantification, or multi-gene normalization across multiple reference genes simultaneously.

## Known failure modes

- Missing required Ct values or efficiencies returns a validation error
- referenceStable set to false may be rejected or flagged as invalid input
- Ct values or efficiencies outside expected biological range may still be accepted due to wide numeric limits but produce nonsensical ratios
- Payment failure via x402 protocol prevents computation
- Malformed body type or non-JSON content type causes request rejection

## How this service works

Calculate a Pfaffl expression ratio from supplied Ct values and amplification efficiencies; require a declared stable reference. No diagnostic interpretation.

## Output

Returns a computed Pfaffl relative expression ratio result object, along with metadata including the offer ID (biology-qpcr-relative-expression), version, input digest, receipt digest, amount in base units, and any boundaries. No diagnostic interpretation is provided — only the numerical expression ratio.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "$schema": "https://json-schema.org/draft/2020-12/schema",
 "required": [
  "input"
 ],
 "properties": {
  "input": {
   "type": "object",
   "required": [
    "type",
    "method",
    "bodyType",
    "body"
   ],
   "properties": {
    "body": {
     "type": "object",
     "required": [
      "dataClass",
      "targetSampleCt",
      "targetControlCt",
      "referenceSampleCt",
      "referenceControlCt",
      "targetEfficiency",
      "referenceEfficiency",
      "referenceStable"
     ],
     "properties": {
      "dataClass": {
       "enum": [
        "public",
        "synthetic"
       ],
       "type": "string"
      },
      "targetSampleCt": {
       "type": "number",
       "maximum": 1000000000000,
       "minimum": -1000000000000
      },
      "referenceStable": {
       "type": "boolean"
      },
      "targetControlCt": {
       "type": "number",
       "maximum": 1000000000000,
       "minimum": -1000000000000
      },
      "targetEfficiency": {
       "type": "number",
       "maximum": 1000000000000,
       "minimum": -1000000000000
      },
      "referenceSampleCt": {
       "type": "number",
       "maximum": 1000000000000,
       "minimum": -1000000000000
      },
      "referenceControlCt": {
       "type": "number",
       "maximum": 1000000000000,
       "minimum": -1000000000000
      },
      "referenceEfficiency": {
       "type": "number",
       "maximum": 1000000000000,
       "minimum": -1000000000000
      }
     },
     "additionalProperties": false
    },
    "type": {
     "type": "string",
     "const": "http"
    },
    "method": {
     "enum": [
      "POST"
     ],
     "type": "string"
    },
    "bodyType": {
     "enum": [
      "json",
      "form-data",
      "text"
     ],
     "type": "string"
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object",
     "required": [
      "version",
      "offerId",
      "amountBaseUnits",
      "inputDigest",
      "result",
      "boundaries",
      "receiptDigest"
     ],
     "properties": {
      "result": {
       "type": "object"
      },
      "offerId": {
       "enum": [
        "biology-qpcr-relative-expression"
       ],
       "type": "string"
      },
      "version": {
       "enum": [
        "maha-microproducts/0.1"
       ],
       "type": "string"
      },
      "bou
… (truncated)
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/qpcr-relative-expression-calculator-pfaffl-method-2c229b94/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from www.mahastrategies.com](https://www.zero.xyz/host/www.mahastrategies.com/llms.txt)