SCC Antigen Unit Converter
SCC Antigen Unit Converter
ng/mL and µg/L are the same number for squamous cell carcinoma antigen. The trap is contamination: the protein is abundant in skin, saliva and sweat, so a contaminated sample reads high with no disease behind it.
SCC Antigen converter
Mass ladder onlySCC antigen 0.9 ng/mL
Formula and conversion factors
pg/mL = ng/mL × 1000
- ng/mL = µg/L
- a nanogram per millilitre and a microgram per litre are the same concentration, so nothing is calculated between them
- no molar unit
- SCC antigen is a serpin family protein reported as a mass concentration against an assay calibrator; no clinical threshold is written in molar units
- contamination
- the antigen is abundant in normal squamous epithelium and in the saliva and sweat that derive from it, so material transferred onto the tube or into the sample raises the result artefactually
- assay dependence
- reference limits are platform-specific and differ between the sexes on some assays, so use the interval on the report and keep serial samples on one analyser
Worked example
SCC antigen 0.9 ng/mL
0.9 ng/mL = 0.90 µg/L — the two units are identical
0.9 × 1000 = 900 pg/mL
No band is shown: the cut-off printed on your own report is the one that applies
The three units
| Unit | Relationship | Example |
|---|---|---|
| ng/mL | The usual reporting convention | 0.90 |
| µg/L | Identical to ng/mL | 0.90 |
| pg/mL | ng/mL × 1000 | 900 |
Why an SCC antigen can be high without cancer
| Cause | Note |
|---|---|
| Sample contamination | The antigen is abundant in normal squamous epithelium and in saliva and sweat. Skin flakes, saliva or perspiration reaching the sample raise the measured level with no disease present |
| Benign skin disease | Psoriasis, eczema and atopic dermatitis are recognised causes of a raised result, sometimes a marked one |
| Renal impairment | Reduced clearance lifts the level; the Mayo Clinic Laboratories assay note lists kidney insufficiency explicitly |
| Inflammatory lung disease | Asthma and other airway inflammation can raise it |
| Benign gynaecological and liver disease | Cervical inflammation, and liver disease, are both described |
| Indicative reference figures | Mayo Clinic Laboratories quote <2.00 µg/L in males and <1.67 µg/L in females on the BRAHMS Kryptor assay — one platform's figures, not universal limits |
A marker that a careless sample can invent
SCC antigen is reported in ng/mL and in the numerically identical µg/L, with pg/mL a thousand times larger, so the conversion itself is trivial. The antigen, originally described as TA-4, is a member of the serpin family of protease inhibitors expressed by squamous epithelium. It is measured as a mass concentration against an assay calibrator rather than weighed, so there is no molar unit and no molar column on this page.
The pre-analytical trap is the thing to know first. The same protein that marks squamous tumours is abundant in ordinary squamous epithelium — in skin, and in the saliva and sweat that come from it. Material transferred into a sample or onto a tube during collection or handling therefore raises the measured concentration with nothing wrong in the patient at all. A puzzlingly high SCC antigen in someone whose imaging is clear is a result to repeat on a carefully collected sample before it is believed.
Benign disease raises it too, and the commonest reasons are dermatological. Psoriasis, eczema and atopic dermatitis all lift the level, sometimes substantially, because the antigen is a product of the same epithelium the disease inflames. Renal impairment raises it by reducing clearance, and inflammatory airway disease such as asthma can as well. None of these is exotic, which is why a single raised result in isolation carries very little weight.
Where the test does contribute is in squamous cell carcinoma of the cervix, head and neck, lung and oesophagus, as a prognostic marker before treatment and for detecting recurrence during follow-up in disease that has already been diagnosed. It is not a screening test and it does not diagnose anything on its own. This page shows no reference band because the published limits are manufacturer figures — Mayo Clinic Laboratories quote under 2.00 µg/L in men and under 1.67 µg/L in women on the BRAHMS Kryptor assay — and they are not interchangeable between platforms. Use the interval on your own report, keep a monitoring series on one assay, and take the result to a clinician who has the rest of the picture.
Frequently asked questions
Is ng/mL the same as µg/L for SCC antigen?
Yes, they are the same number. pg/mL is a thousand times larger, so 0.90 ng/mL is 0.90 µg/L and 900 pg/mL. There is no molar unit for SCC antigen — every published threshold is a mass concentration.
Can a contaminated sample raise SCC antigen?
Yes, and it is the classic pitfall with this test. The antigen is abundant in normal squamous epithelium and in the saliva and sweat derived from it, so skin flakes, saliva or perspiration reaching the sample can lift the measured level with no disease present. An unexpectedly high result is worth repeating on a fresh, carefully collected sample.
Does psoriasis or eczema raise SCC antigen?
Yes. Benign inflammatory skin conditions including psoriasis, eczema and atopic dermatitis are recognised causes of a raised SCC antigen, because the antigen is a product of the squamous epithelium those conditions involve. Renal impairment and inflammatory airway disease also raise it.
What is SCC antigen used for?
It is used in squamous cell carcinoma of the cervix, head and neck, lung and oesophagus — as a prognostic marker before treatment and for detecting recurrence during follow-up. It is not a screening test and cannot diagnose cancer on its own.
What is a normal SCC antigen?
There is no universal figure. Mayo Clinic Laboratories quote under 2.00 µg/L in males and under 1.67 µg/L in females on the BRAHMS Kryptor assay, but limits differ between platforms and sometimes between the sexes, so the interval printed on your own report is the one that applies.
Related calculators
References
- Mayo Clinic Laboratories. Squamous Cell Carcinoma Antigen, Serum (test 610033): reference values <2.00 mcg/L (males) and <1.67 mcg/L (females) by BRAHMS Kryptor; elevated concentrations may occur in kidney insufficiency, skin disorders such as psoriasis, or inflammatory lung disease such as asthma.
- Cataltepe S, Gornstein ER, Schick C, et al. Co-expression of the squamous cell carcinoma antigens 1 and 2 in normal adult human tissues and squamous cell carcinomas. J Histochem Cytochem. 2000;48(1):113–122.
- Sturgeon CM, Duffy MJ, Hofmann BR, et al. National Academy of Clinical Biochemistry Laboratory Medicine Practice Guidelines for use of tumor markers in liver, bladder, cervical, and gastric cancers. Clin Chem. 2010;56(6):e1–e48.
Medical Disclaimer: The tools and content provided here are for educational and reference purposes only. They are not intended to substitute for professional medical advice, diagnosis, or treatment. Clinical decisions should always be based on the comprehensive assessment of a qualified healthcare professional.