Specimen Collection

EDTA anticoagulant gives falsely elevated results

• Laboratory: separate plasma from red cells if stored longer than 2 hours.

Sample stable for 6 days at 4 ^o C and 30 days at -20 ^o C.

4.5 mL PST Blood (Preferred)

5 mL Heparin Blood
Reference Intervals

Units: mg/L

Reference range: < 90

Uncertainty of Measurement: 10%

Turnaround Time: Within 3 hours
Assay Method

Principle: Absorbance measurement calculation

Assay: Roche Serum Index Gen. 2

Analyser: Cobas c702

Diagnostic Use and Interpretation

Specimen should be collected taking precautions to minimise haemolysis: use a wide-bore needle and syringe, not vacutainer. Draw the blood very slowly with minimum suction.

Plasma needs to be separated from red cells within 2h after blood collection.

For coronary bypass specimens, see Haemolysis.

Recent intravenous iron infusion (such as ferric carboxymaltose ) discolours that plasma and can give a falsely elevated measure of plasma haemoglobin. The half-life of ferric carboxymaltose is about 12hrs so the effect is expected to diminish rapidly in the first 24hrs. The test can still be requested during this time period but should be interpreted with caution.

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