DICOM Attribute

Bits Allocated (0028,0100)

Keyword
BitsAllocated
VR
US
VM
1

Definition

Number of bits allocated for each pixel sample. Each sample shall have the same number of bits allocated. See PS3.5 for further explanation. Enumerated Values: 32

From NEMA PS3.3 §C.7.6.24.

Attribute Metadata

Tag
(0028,0100)
Keyword
BitsAllocated
Name
Bits Allocated
Value Representation (VR)
US
Value Multiplicity (VM)
1
Status
Active
Source
NEMA PS3.6 (table_6-1)

This attribute is part of the current DICOM Standard. Its value representation is US with multiplicity 1.

Used in 30 Modules

This attribute uses the US Value Representation. Multiplicity 1 governs how many values may be encoded.

Integration Notes

Real-world integration guidance for engineers implementing this attribute in Mirth Connect, FHIR gateways, HL7 v2 bridges, and cloud DICOM services. Authoritative source data where available; reference examples and operational notes where they add value.

FHIR Mapping

No direct FHIR ImagingStudy mapping published for this attribute. Some tags map indirectly via the Patient, Endpoint, or ImagingSelection resources — Phase 2b will expand coverage to those.

HL7 v2 Equivalent

No standard HL7 v2 equivalent published for this attribute. Imaging-only attributes (Image Pixel data, technical acquisition parameters, modality-specific values) typically have no HL7 v2 carrier.

Cloud DICOM Support

  • AWS HealthImaging Preserved
  • Azure DICOM Preserved
  • Google Cloud Healthcare Preserved

Bits Allocated — required for pixel data interpretation; preserved by all three vendors as ImageFrame metadata.

Per-vendor source URLs and verification date in src/content/dicom/cloud-support.json#_meta. Status taxonomy: required (mandated on Store), queryable (QIDO-RS matching key), preserved (stored as-is), promoted (AWS top-level metadata), unsupported (stripped/rejected).

Real-World Sample Values

  • 16 CT_small.dcm
  • 8 ExplVR_BigEnd.dcm

Extracted from pydicom test fixtures (MIT, de-identified).

Mirth Connect Example

Sanity-check Bits Allocated against expected modality range — BitsAllocated >32 is invalid for non-floating-point modalities

BitsAllocated >32 is invalid for non-floating-point modalities. Bad values often indicate corruption or vendor non-conformance.

// (0028,0100) Bits Allocated — must be 8, 16, or 32 for image storage SOP classes
var ba = parseInt(String(msg.dataset.attr.(@tag == '00280100').value), 10);
if (ba !== 8 && ba !== 16 && ba !== 32) {
  logger.error('Invalid Bits Allocated: ' + ba + ' — DICOM file likely corrupted');
  router.routeMessageByChannelName('DICOM_QC_Quarantine', message.getRawData());
  destinationSet.removeAll();
  return;
}

Reference only — validate before production. Snippets are starting points, not turnkey solutions. Always test against your channel's specific message structure and your facility's interface specification. See Mirth Connect User Guide + NEMA PS3.6 + your vendor conformance statement for authoritative specification.

Common Operational Errors

  • high BitsAllocated=8 on 16-bit modality output causes pixel overflow

    Diagnosis: Modality firmware bug: modality actually acquires 12-bit radiographic data but writes BitsAllocated=8 in the DICOM header. Storing in 8-bit truncates the dynamic range; window/level presets from the header describe values beyond the stored range.

    Fix: Validate BitsAllocated against the modality's known acquisition bit depth. For CR/DX/CT, BitsAllocated should be 16. If 8 appears, reject with a validation error and alert the modality support team — usually a firmware bug.

Reference only — validate before applying a fix. Scenarios are drawn from common DICOM/HL7 v2 integration patterns; reproduce against your environment before acting on any diagnosis. See NEMA PS3.6 + your vendor conformance statement for authoritative specification. Severity levels: high (data-loss / patient-safety), medium (workflow disruption), low (cosmetic).

DICOM Integration Services

Saga IT builds production DICOM integrations across Mirth Connect, FHIR gateways, and cloud imaging platforms. If you're working with BitsAllocated or the broader (0028,0100) context: