State of California—Health and Human Services Agency
California Department of Public Health

February 18, 2026

TO:

Public Health Laboratory Partners

SUBJECT:

Reporting Multiplex Respiratory Panels and Subtyped Influenza A&B and RSV Results – Addendum

Dear Public Health Laboratory Partner,

Thank you for your continued commitment to timely and accurate reporting of SARS-CoV-2, Influenza A & B, and RSV results. Your efforts play a vital role in protecting the health of Californians. This addendum to the CDPH ELR reporting guidanc e (PDF) for multiplex respiratory panels and subtyped Influenza A&B updates the requirements to include reporting of testing kits and unsubtypable influenza results from public health laboratories, in order to further enhance data completeness.

Highlights

Laboratories should continue to follow the CDPH ELR reporting guidance (PDF) for reporting all results from multiplex respiratory panels and subtyped Influenza A and B, and RSV.
For any inconclusive or unsubtypable result, include the following information in the NTE segment using this format: Unsubtypable. Ct is [Ct value].
Report the testing kit information, including brand names (e.g., BioFire, CDC), in OBX-17.

Testing kit information

Report the testing kit information in OBX-17.1 (20 characters limit) or OBX17.2 (more than 20 characters) component. Please ensure that the testing kit description clearly indicates the testing kit brand such as BioFire RP2.1 panel, CDC reagents, etc.

Reporting of inconclusive or unsubtypable influenza testing

During manual review of rRT-PCR results, laboratories should evaluate all assay targets to determine whether a specimen meets the criteria for inconclusive influenza A H1 or unsubtypable influenza A. When available, report Ct values along with the appropriate designation and any required contextual details in the NTE (comment/note) field of the HL7 message (see table below)

Influenza A Subtyping Result Interpretation and Reporting

Inf A	H3	pdm Inf A	pdm H1	Interpretation	Report in NTE (comment) segment
POS Ct [Ct value]	NEG	NEG	NEG	Unsubtypable	Unsubtypable, fluA Ct is [Ct value]. E.g: Unsubtypable, fluA Ct is 35
POS Ct [Ct value]	NEG	POS	NEG	A/Inconclusive H1	Inconclusive A, fluA Ct is [Ct value].
POS Ct [Ct value]	POS	POS	NEG	A/Inconclusive H1	Inconclusive A, fluA Ct is [Ct value].

For influenza B results, laboratories should report lineage information (e.g., Victoria or Yamagata) when available. If influenza B lineage typing is attempted but a lineage cannot be determined, this should be documented “Unable to lineage type, Ct is [Ct value]” in the NTE (note/comment) segment of Inf B HL7 message.

Samples deemed unsubtypable or inconclusive A/H1 with Ct ≤ 35 should also be submitted to VRDL for further testing according to the sample testing guidance.

CDPH appreciates your efforts to report timely, complete and accurate SARS-CoV-2, Influenza A & B, and RSV results to improve the health of Californians. Questions regarding testing and ELR setup should be directed to calredieelr@cdph.ca.gov for assistance. Questions related to public health laboratory (PHL) reporting guidance should be sent to InfluenzaSurveillance@cdph.ca.gov.

Thank you!

Below is an example of a properly formatted multiplex HL7 result, updated to demonstrate reporting of the testing kit for all tests and Ct value of InfA when subtyping fails to identify an influenza A subtype (highlighted).

Note that each OBX-3.1 contains a virus-specific LOINC.

Do not use the LOINC associated with the overall multi-pathogen test when reporting results in the OBX segments.

OBR|1||55555718120^TESTLAB^2.16.840.1.113883.3.362.90.100^ISO|95941-1^Influenza virus A and B and SARS-CoV-2 (COVID-19) and Respiratory syncytial virus RNA panel - Respiratory specimen by NAA with probe detection|||202411011633-0800|||||||||1234567890^SMITH^JANE^^^^^^NPI&2.16.840.1.113883.4.6&ISO^^^^NPI|^WPN^PH^^^555^7773333|||||20241106044205-0500|||F||||||

OBX|1|CWE|94565-9^SARS coronavirus 2 RNA^LN||260415000^Not Detected^SCT^NOTDET^Not Detected^L^20230301^1||Not Detected|N^Normal|||F|||202411011633-0800|||^BioCode CoV-2 Flu Plus Assay_Applied BioCode, Inc.||20241105223532-0500||||TESTLAB^D^^^^CLIA&2.16.840.1.113883.4.7&ISO^XX^^^05D0123456|1616 CAPITOL AVE^^SACRAMENTO^CA^95814

OBX|2|CWE|82166-0^Influenza virus A RNA^LN||260373001^Detected^SCT^DETEAB^Detected^L^20230301^1||Not Detected|A^Abnormal^HL70078^^^^HL7 v2.8.2|||F|||202411011633-0800|||^BioCode CoV-2 Flu Plus Assay_Applied BioCode, Inc.||20241105223532-0500||||TESTLAB^D^^^^CLIA&2.16.840.1.113883.4.7&ISO^XX^^^05D0123456|1616 CAPITOL AVE^^SACRAMENTO^CA^95814

OBX|3|CWE|82167-8^Influenza virus A H1 RNA^LN||260415000^Not Detected^SCT^NOTDET^Not Detected^L^20230301^1||Not Detected|N^Normal|||F|||202411011633-0800|||^BioCode CoV-2 Flu Plus Assay_Applied BioCode, Inc.||20241105223532-0500||||TESTLAB^D^^^^CLIA&2.16.840.1.113883.4.7&ISO^XX^^^05D0123456|1616 CAPITOL AVE^^SACRAMENTO^CA^95814

OBX|4|CWE|68986-9^Influenza virus A H5a RNA^LN||260373001^Detected^SCT^DETEAB^Detected^L^20230301^1||Not Detected|A^Abnormal^HL70078^^^^HL7 v2.8.2|||F|||202411011633-0800|||^BioCode CoV-2 Flu Plus Assay_Applied BioCode, Inc.||20241105223532-0500||||TESTLAB^D^^^^CLIA&2.16.840.1.113883.4.7&ISO^XX^^^05D0123456|1616 CAPITOL AVE^^SACRAMENTO^CA^95814

OBX|5|CWE|82169-4^Influenza virus A H3 RNA^LN||260415000^Not Detected^SCT^NOTDET^Not Detected^L^20230301^1||Not Detected|N^Normal|||F|||202411011633-0800|||^BioCode CoV-2 Flu Plus Assay_Applied BioCode, Inc.||20241105223532-0500||||TESTLAB^D^^^^CLIA&2.16.840.1.113883.4.7&ISO^XX^^^05D0123456|1616 CAPITOL AVE^^SACRAMENTO^CA^95814

OBX|6|CWE|82170-2^Influenza virus B RNA^LN||260415000^Not Detected^SCT^NOTDET^Not Detected^L^20230301^1||Not Detected|N^Normal|||F|||202411011633-0800|||^BioCode CoV-2 Flu Plus Assay_Applied BioCode, Inc.||20241105223532-0500||||TESTLAB^D^^^^CLIA&2.16.840.1.113883.4.7&ISO^XX^^^05D0123456|1616 CAPITOL AVE^^SACRAMENTO^CA^95814

OBX|7|CWE|30075-6^RSV A RNA NAA+probe Ql (Specimen)^LN||260373001^Detected^SCT^NOTDET^Not Detected^L^20230301^1||Not Detected|A^Abnormal|||F|||202411011633-0800|||^BioCode CoV-2 Flu Plus Assay_Applied BioCode, Inc.||20241105223532-0500||||TESTLAB^D^^^^CLIA&2.16.840.1.113883.4.7&ISO^XX^^^05D0123456|1616 CAPITOL AVE^^SACRAMENTO^CA^95814

OBX|8|CWE|30076-4^RSV B RNA NAA+probe Ql (Specimen)^LN||260415000^Not Detected^SCT^NOTDET^Not Detected^L^20230301^1||Not Detected|N^Normal|||F|||202411011633-0800|||^BioCode CoV-2 Flu Plus Assay_Applied BioCode, Inc.||20241105223532-0500||||TESTLAB^D^^^^CLIA&2.16.840.1.113883.4.7&ISO^XX^^^05D0123456|1616 CAPITOL AVE^^SACRAMENTO^CA^95814

NTE|1|L|Unsubtypable, fluA Ct is 34.2 |

SPM|1|^55555718120&TESTLAB&2.10.640.1.113883.3.362.90.100&ISO||445297001^Nasal Swab^SCT^^^^2.5.1||||71836000^Nasopharyngeal structure^SCT|||||||||202411011633-0800|202411020316-0800||||||||||||