---
type: "fhirpath-function"
title: "FHIRPath Function: allTrue"
function: "allTrue"
category: "Existence"
section: "5.1.4"
source: "fhirpath/functions.json"
---
# FHIRPath Function: allTrue
Takes a collection of Boolean values and returns `true` if all the items are `true`. If any items are `false`, the result is `false`. If the input is empty (`{ }`), the result is `true`.

The following example returns `true` if all of the components of the Observation have a value greater than 90 mm[Hg]:

``` fhirpath
Observation.select(component.value > 90 'mm[Hg]').allTrue()
```
## Summary
- **Category**: Existence
- **Section**: `5.1.4`
- **Return Type**: `Boolean`
- **Empty Input Result**: `true`
- **Errors on Multiple Input**: `false`
## Description
Takes a collection of Boolean values and returns `true` if all the items are `true`. If any items are `false`, the result is `false`.
## Arguments
- none
## Type Mapping
- `Boolean-Boolean`
## Example
```fhirpath
Observation.select(component.value > 90 'mm[Hg]').allTrue()
```