Specimen Collection

Sample stability:

• 5 days at 20-25 ^o C
• 14 days at 2-8 ^o C
• 6 months at -20 ^o C

4.5 mL PST Blood (Preferred)

0.5 mL Paediatric Micro-PST Blood (Preferred)

4 mL Heparin Blood

4 mL Plain Blood

3.5 mL SST Blood

0.5 mL Paediatric Microsample Blood
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.

Uncertainty of Measurement: 6%

Maternal Serum Screen

Turnaround Time: Within 3 hours
Assay Method

Principle : Sandwich type immunoassay with chemiluminescence detection

Reagents : Roche AFP kit

Analyser : Cobas e801

Diagnostic Use and Interpretation

Serum alpha-fetoprotein is used for the detection and monitoring of hepatocellular carcinoma and some germ cell tumours . (For detecting neural tube defects or Down syndrome, see Maternal Serum Screen )

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.

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.

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.

References :
1. Blohm ME, Vesterling-Horner D, Calaminus G, Gobel U. Alpha 1-fetoprotein (AFP) reference values in infants up to 2 years of age. Pediatric hematology and oncology 1998;15(2):135-42.

2. Soldin et al. Pediatric Reference Intervals. 6th ed. AACC Press, 2007.

3. CSF reference interval: Mayo Medical Laboratories 2003 Test Catalog.

Contact Information

Emails to chemicalpathologist@adhb.govt.nz will receive priority attention from the on-call chemical pathologist.

If the query concerns a specific patient please include the NHI number in your email.

If email is not a suitable option, please contact the on-call chemical pathologist via Lablink (Auckland City Hospital ext. 22000 or 09-3078995).

Individual chemical pathologists may be contacted but will not be available at all times.

After-hours : contact Lablink (Auckland City Hospital ext. 22000 or 09-3078995) or hospital operator for on duty staff after hours.

Dr Samarina Musaad (Clinical Lead) : SamarinaM@adhb.govt.nz ext. 22402

Dr Cam Kyle: CampbellK@adhb.govt.nz ext 22052

Dr Weldon Chiu: WeldonC@adhb.govt.nz ext. 23427

Dr Campbell Heron: CHeron@adhb.govt.nz ext. 23427

Dr Sakunthala Jayasinghe: Sakunthala@adhb.govt.nz ext. 23427

Last updated at 15:26:00 06/01/2025