Specimen Collection

If iron studies is requested the following tests will be performed:

• plasma/serum iron
• TIBC (total iron-binding capacity )
• Iron saturation
• ferritin

Sample stability:

• 7 days at 15-25 ^o C
• 3 weeks at 2-8 ^o C
• several years at -20 ^o C

4.5 mL PST Blood (Preferred)

0.5 mL Paediatric Micro-PST Blood (Preferred)

5 mL Heparin Blood

4 mL Plain Blood

3.5 mL SST Blood

0.5 mL Paediatric Microsample Blood

0.5 mL Paediatric Micro-heparin Blood
Reference Intervals

Units: umol/L

Reference intervals:

0 - 2 months	10-31
2 mths - 1 year	4-27
1 - 3 years	5-23
3 - 10 years	6-25
10 - 18 years	8-32
Adult	10-30

Uncertainty of Measurement: 5%

Turnaround Time: Within 3 hours
Assay Method

Iron:

Principle : Colorimetric

Reagents: Roche IRON2 kit

Analyser: Cobas c702

Diagnostic Use and Interpretation

Plasma iron concentrations are generally higher in the morning, but the diurnal variation is inconsistent. Concentrations may also vary widely from day to day in the same patient.

Causes of increased plasma iron : iron poisoning, haemochromatosis, anaemias which are not due to iron deficiency especially when treated with transfusions, and liver disease.

Causes of decreased plasma iron : iron deficiency anaemia, anaemia associated with chronic disorders.

TIBC (transferrin): increased in iron deficiency. Decreased in iron overload, inflammation & infection, and liver disease.

Differentiating iron-deficiency anaemia from that of chronic disease can be difficult. Ferritin is helpful if it is low. However ferritin is increased nonspecifically in many inflammatory disorders; the ferritin concentration may be normal, or increased, even though the patient is iron deficient. Measurement of the level of soluble transferrin receptors (sTfR ) may be helpful in this context.

The table shows typical findings in disease states.

.	Normal	Iron deficiency	Anaemia of chronic disease	Iron overload	Liver disease
Serum iron	Normal	Decreased	Decreased	Increased	Increased or normal
TIBC	Normal	Increased	Normal or Decreased	Decreased	Decreased or Normal
Saturation	Normal	Decreased	Decreased usually	Increased	Normal
Ferritin	Normal	Decreased	Normal or Increased	Increased	Increased
StfR	Normal	Increased	Normal or Slightly Increased	Normal	Normal

See also:

Ferritin

Soluble Transferrin Receptors (sTfR)

Because of diurnal variation, a morning (0800 h - 0900 h) specimen is preferred

Note: Recent intravenous iron infusion (such as ferric carboxymaltose) significantly increases serum iron. The half-life of ferric carboxymaltose is about 12hrs, however given the large iron load with a single dose it would not be recommended to repeat iron studies for at least 10 days without clear indication.

Reference(s):

1. Geisser P and Burckhardt S. The pharmacokinetics and pharmacodynamics of iron preparations . Pharmaceutics. 2011, 3, 12-33 .

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