At a glance
| Analyte | Carbohydrate antigen 19-9 |
|---|---|
| Also called | CA-19-9, Carbohydrate antigen 19-9 |
| Method | Two-site sandwich chemiluminescence immunoassay |
| Sample type | Serum, Plasma |
| Panel | Tumour marker |
| Discipline | CLIA immunoassay |
| Brand | Mindray |
What CA 19-9 measures
CA 19-9 is used in monitoring and follow-up of pancreatic and biliary conditions under the direction of the requesting physician. It carries a genuine and often overlooked limitation: the antigen is built on the Lewis blood group system, and a small proportion of people lack the enzyme needed to produce it at all. In those individuals the marker stays low regardless of disease, so a normal result in a Lewis-negative patient means nothing. It is also raised by any cause of cholestasis, so an obstructed biliary tree elevates it independently of what caused the obstruction. Both facts push interpretation firmly toward the trend and toward the clinician holding the full picture.
How Philippine laboratories run it
Requested by gastroenterology, hepatobiliary and oncology services on patients under follow-up, so volume is low and concentrated in tertiary hospitals. The cholestasis caveat has a practical consequence worth knowing on the bench: a patient with an obstructed biliary tree can show a markedly raised value that falls substantially once the obstruction is relieved, without any change in the underlying condition being followed. Reading such a fall as a treatment response is a real risk, which is why the result belongs with the clinical context rather than standing alone.
Analyzers it runs on
Calibrator, controls and companion tests
Delivered with the rest of the tumour marker panel, on the same schedule as CA 19-9.
Storage and handling
Refrigerated, upright, and not frozen.
Buying CA 19-9 in the Philippines
CA 19-9 is supplied for the CL-2600i and CL-900i. We deliver it with CEA and AFP, because a run held up waiting on a separate order costs the same shift a stock-out does. Delivery is scheduled against your monthly CA 19-9 count, so the bench is not rationing tests in the last week of the month. How we plan clia immunoassay supply.
Questions about CA 19-9
Can a patient have a normal CA 19-9 despite significant disease?
Yes. The antigen is built on the Lewis blood group system, and a small proportion of the population lacks the enzyme required to produce it. In those individuals the marker remains low whatever is happening clinically, so a normal result carries no reassurance. This is one of the clearest illustrations of why these markers are followed rather than relied on.
Order CA 19-9
Tell us your monthly CA 19-9 volume and we will quote a supply schedule for CL-2600i. We reply within one business day.
Request a quotation