Tosoh HLC-723GX LIS Integration: HbA1c Without Retyping

The HLC-723GX is a quiet workhorse. It sits on a bench, runs glycohemoglobin, and produces numbers that go straight into a diabetes management decision. In a great many labs it is also one of the last analyzers still being read off a screen and typed into the LIS by hand — because its output does not look like anything a standard middleware installation expects.

LISBridge now parses it natively. This post covers what the instrument sends, what LISBridge reads, and the one analyzer setting you need to get right before connecting.

Why HbA1c Stays in the Lab

It is worth being clear about why this analyzer is not going away.

The American Diabetes Association's Standards of Care in Diabetes — 2026 restricts point-of-care A1C for diagnosis to FDA-approved devices operated inside CLIA-certified laboratories performing moderate-complexity or higher testing, with the assay NGSP-certified as traceable to the DCCT reference method.

Read plainly: diagnosis-grade HbA1c does not move to the clinic counter. It stays on a bench analyzer, in a lab, under a quality programme. The HLC-723GX and instruments like it are exactly what that requirement describes, and they will be running for years.

Which makes the transcription question permanent rather than temporary. A result that must be produced in a lab is a result that must get from that lab into a record — and if the path between them is a person retyping numbers, that path has an error rate attached to it.

The GX Format Is Neither HL7 Nor ASTM

Here is what makes this instrument interesting, and what makes most middleware skip it.

The HLC-723GX does not speak HL7. It does not speak ASTM E1394. It speaks the GX format, described in the HLC-723GX Host Connection Specifications, and the GX format is a fixed-width, delimiter-less ASCII record.

There are no pipes. No carets. No record-type letters at the start of a line. There is nothing to split on, because the fields are defined by their byte positions and nothing else. A parser that works by finding separators has nothing to find.

The record travels inside Tosoh's HI-LEVEL handshake: each record is framed as <STX>, the record text, <ETX>, then a one-byte BCC checksum — a block check character computed as an XOR across the frame. The host acknowledges each record with ACK or rejects it with NAK, and the analyzer sends <EOT> after the final record of a data set.

That BCC is the detail that catches naive implementations. Being an XOR byte, it can land on a printable ASCII character — and a parser that "cleans" the incoming stream before reading it will happily treat that checksum byte as part of the data, leaving a stray character dangling on the end of the sample ID field. LISBridge parses the HLC-723GX on the raw byte stream rather than a cleaned one, for exactly this reason, and recovers the sample-number and sample-ID field widths structurally rather than by inferring them from total record length.

This is the general case, not a Tosoh curiosity. Real lab floors contain analyzers that speak fixed-width records, analyzers that wrap vendor framing around a standard, and analyzers that deposit XML on a file server. "We support HL7 and ASTM" is not an answer to any of them. More on that in protocol support.

What LISBridge Reads From the HLC-723GX

The parser reads the twelve components of the chromatogram plus the derived values, and specifically captures:

• Total A1% — the total glycated hemoglobin fraction.
• SA1c on the JDS scale — the Japanese Diabetes Society standardisation.
• SA1c on the NGSP scale — the DCCT-traceable value most laboratories report.
• SA1c on the Mono S scale — the Swedish standardisation.
• SA1c (IFCC) in mmol/mol — the SI-unit reference value.
• CALIB type and flag judgment — the analyzer's own assessment of the run.
• Specimen vs. calibrator — carried structurally in the record.

Two things follow from that list.

First, because all four HbA1c scales are read rather than just the one you happen to report, the mapping decision is yours. A lab reporting NGSP maps NGSP; a lab reporting IFCC mmol/mol maps IFCC; a lab reporting both dual-reports without a vendor ticket. You map any analyzer parameter to any LIS field yourself.

Second, the specimen-versus-calibrator distinction is read at parse time, which means calibrator runs are classified as calibration traffic and routed out of the patient pipeline before delivery. A calibration value cannot arrive in a patient chart, because it never enters the path that leads there. The same message-class handling that applies to QC and calibration across the rest of the platform applies here — see QC results are not patient results.

Set TRANS MODE to GX FORM — and What We Deliberately Do Not Do

One setting matters, and it is worth being precise about it.

On the analyzer, TRANS MODE must be set to GX FORM. This is the factory default, so on most instruments there is nothing to change — but if the analyzer has been reconfigured at any point, check it before you connect.

The reason is a design decision we made on purpose. The HLC-723GX firmware can also transmit in the G8, G9, G7 and GHbV formats, which are output modes belonging to other Tosoh instruments. LISBridge does not auto-route those formats.

That is a deliberate limitation, not a gap. Those formats carry no identity token — nothing inside the record says which analyzer model produced it. Software that accepted them would be guessing at the instrument of origin, and a wrong guess means attributing one analyzer's result to another analyzer's patient. On an HbA1c value feeding a diabetes diagnosis, that is not a risk worth taking to save a configuration step.

So: GX FORM, and a parser that knows with certainty what it is reading.

Connecting It: Setup Walkthrough

1. Check the analyzer's transmission mode. In the HLC-723GX host settings, confirm TRANS MODE is GX FORM and that HI-LEVEL handshaking is enabled.
2. Note the serial parameters. Baud rate, data bits, parity and stop bits as configured on the instrument — you will mirror these on the LISBridge side.
3. Cable it. The HLC-723GX connects over RS-232 serial. Run the cable to the machine that will host LISBridge; a USB-to-serial adapter is fine where the host has no native port. See device connectivity for transport details.
4. Add the instrument in LISBridge. Select the Tosoh HLC-723GX from the instrument catalog, choose the serial port, and enter the matching serial parameters.
5. Run a specimen. Watch the connection view as the analyzer transmits. You should see the record arrive, the handshake complete, and the parsed components appear.
6. Map your fields. Decide which HbA1c scale or scales go to which LIS fields, and map them. This is the only decision in the process that is genuinely yours to make.
7. Validate. Run known specimens end to end and confirm what lands in the LIS matches what the analyzer reported. This step belongs to you regardless of middleware, and it is the one that should not be rushed.

The whole sequence is configuration, not development. There is no protocol work in it, because the protocol work is already in the product. For the wider picture of how connection, parsing, processing and delivery fit together, see how it works.

FAQ

Is the HLC-723GX bidirectional — can LISBridge send it orders?

No. The HLC-723GX is supported as a result parser only. It is not one of the 17 order-capable instruments in the catalog. Results flow from the analyzer to your LIS; test orders are not sent to it. If bidirectional ordering on this bench matters to you, say so — but the honest answer today is results only.

My analyzer is set to G8 format. Will it work?

Not automatically, and that is intentional. Set TRANS MODE to GX FORM. The G8, G9, G7 and GHbV formats carry no instrument identity token, so auto-routing them would risk attributing a result to the wrong analyzer. GX FORM is the factory default, so this is usually a check rather than a change.

Which HbA1c value gets sent to my LIS?

Whichever you map. LISBridge reads total A1%, SA1c on JDS, NGSP and Mono S scales, and SA1c (IFCC) in mmol/mol. You map the scale or scales your lab reports to the LIS fields you use. Dual reporting is a mapping choice, not a development request.

What happens to calibrator runs?

They are identified as calibration traffic at parse time and routed out of the patient pipeline. A calibrator value cannot be delivered as a patient result because it never enters the delivery path.

Does this need a network connection to work?

No. LISBridge is a native desktop application that runs locally and works offline, with device-based licensing enforced without an internet check. An internet outage does not stop the HLC-723GX link, and results are stored locally in crash-safe storage that survives a power cut.

What if the serial link drops mid-transmission?

The connection re-establishes itself with exponential backoff and jitter rather than waiting for someone to notice. The HI-LEVEL handshake means an incomplete record is NAKed rather than silently accepted, so a truncated transmission does not become a partial result.

The Short Version

Guidelines keep diagnosis-grade HbA1c on a lab bench analyzer, which means the HLC-723GX is part of your workflow for the foreseeable future. It speaks a fixed-width, delimiter-less dialect that is neither HL7 nor ASTM, wrapped in an STX/ETX/BCC handshake, and most middleware does not read it at all.

LISBridge does — all four HbA1c scales, specimens separated from calibrators, over a serial cable, with TRANS MODE set to GX FORM. Connecting it takes a cable and a configuration screen.

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