Diagnostic Use
Serum alpha-fetoprotein is used for the detection and monitoring of hepatocellular carcinoma and some germ cell tumours.
For detection of aneuploidy in pregnancy, see Maternal Serum Screening (MSS).
Interpretation
About 85% of hepatocellular carcinomas are associated with very high levels of serum alpha-fetoprotein (> 100 ug/L), but a normal level does not exclude the diagnosis. It may also be observed in other cancers, e.g. colon cancer.
Moderate increases (up to 100 ug/L) are seen in association with liver cell regeneration e.g. in cirrhosis, chronic active hepatitis.
Increased levels also occur with germ cell tumours of the ovary or testis, or teratomas. These tumours also frequently produce hCG. Additionally, AFP and hCG are increased in pregnancy.
A rare cause for raised AFP is Familial Persistence of AFP. This is an asymptomatic condition with no adverse clinical consequences. The raised AFP level is found in other family members.
The half-life of AFP in vivo is about 5 days in adults. In neonates, AFP declines with a half-life of 6 days until 28 days of age; after this the rate of decline is slower – see table above.
Reference Intervals
Units: ug/L
|
Age
|
Term Baby (37 week +)
|
Prem Baby (<37 week)
|
|
0 days
|
9,100-190,000
|
31,000-80,0000
|
|
1 day
|
8,000-166,000
|
280,000-710,000
|
|
2 days
|
7,000-145,000
|
25,000-630,000
|
|
3 days
|
6,000-126,000
|
22,000-560,000
|
|
4 days
|
5,300-110,000
|
19,500-500,000
|
|
5 days
|
4,600-96,500
|
17,400-445,000
|
|
6 days
|
4,000-84,500
|
15,300-393,000
|
|
7 days
|
3,500-73,500
|
12,600-350,000
|
|
8-14 days
|
1,500-59,000
|
6,000-312,000
|
|
15-21 days
|
575-23,000
|
2,700-151,000
|
|
22-28 days
|
300-6,300
|
1,200-120,000
|
|
29-45 days
|
30-5,700
|
400-80,000
|
|
46-60 days
|
16-2,000
|
90-39,000
|
|
61-90 days
|
6-1,000
|
20-22,000
|
|
91-120 days
|
3-420
|
10-18,500
|
|
121-150 days
|
2-220
|
4-8,300
|
|
151-180 days
|
1-130
|
3-4,350
|
|
181-270 days
|
0-87
|
3-2,600
|
|
271-365 days
|
0-87
|
3-830
|
|
1 to 2 years
|
0-87
|
0-370
|
|
2y – Adult (non-pregnant):
|
< 10
|
|
Pregnancy
|
|
14 weeks (median)
|
23
|
|
22 weeks (median)
|
60
|
|
30 weeks (median)
|
180
|
CSF : < 1.5 ug/L
Note : The median values for pregnancy are only approximate and should not be used for screening for neural tube defects or other foetal abnormalities.
See Maternal serum screen.
Test Method
Performed in: LabPlus Automation
Principle : Sandwich type immunoassay with chemiluminescence detection
Reagents : Roche assay
Analyser : Roche Cobas