Sample must be protected from light.
Do not separate.
Blood should be taken at least 8 hours after supplementation, ideally after a period of fasting.
This test may be vetted by a pathologist.
The clinical information for the test must be clearly written on the request form. If clinical information is not provided, or does not provide sufficient justification for the test, the test may be declined.
Declined tests :
If a test is declined, the specimen will be held for a reasonable period (usually 3 weeks but dependant on the stability of the sample). Medical practitioners seeking approval for a declined test should email the on-call Chemical Pathologist ( chemicalpathologist@adhb.govt.nz ) , giving the patient's name and NHI number and the clinical justification for the test. If unable to email, call the on-call Chemical Pathologist via Lablink (09-3078995) and identify yourself as a doctor.
If Vitamin B6 is also required then two tubes should be collected.
174 - 471 nmol/L
UoM: 16%
Principle : High performance liquid chromatography with fluorescence detection
Background
Vitamin B 2 (riboflavin) is an essential, water-soluble component of coenzymes such as FAD and FMN. Animal meats and offal are rich sources of riboflavin, though vegetables and milk from cows and humans are also important sources. The dietary requirement for riboflavin is higher in persons with a higher energy intake, larger body size, in pregnancy and in lactation. Testing whole blood B 2 levels may be useful in identifying riboflavin deficiency.
Deficiency
Riboflavin deficiency is not expected in most persons eating a fairly balanced diet. As FAD and FMN are important for many normal cellular functions, riboflavin deficiency may be difficult to identify. The classical deficiency syndrome includes:
- Sore throat and hyperaemia
- Oropharyngeal mucous membrane oedema
- Changes to the skin and mucous membranes of the tongue, lips and angles of the mouth
- Seborrhoeic dermatitis
- Normochromic normocytic anaemia
- Often associated with other complicating deficiencies
According to MoH nutrition data, about 5% of New Zealanders were estimated to have inadequate intake. It is not clear how many of these people had a true deficiency of riboflavin.
Excess
In contrast, there is no clear toxic level for riboflavin and high intakes are not known to cause adverse effects. However, high concentrations of riboflavin may interact with some laboratory tests, causing interference.
Reporting
This HPLC method allows direct measurement of riboflavin, FMN and FAD in whole blood to assess riboflavin status. Only FAD will be reported.
References
1. Tietz Textbook of Clinical Chemistry and Molecular Diagnostics, 6E
2. A Focus on Nutrition: Key findings of the 2008/09 New Zealand Adult Nutrition Survey
3. Cuerq, C., Peretti, N., Chikh, K., Mialon, A., Guillaumont, M., Drai, J., & Blond, E. (2015). Overview of the in vitro stability of commonly measured vitamins and carotenoids in whole blood. Annals of Clinical Biochemistry 52(2), 259-269. https://doi.org/10.1177/0004563214542471
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
EDTA Whole blood - do not separate.
Samples should be sent light protected and frozen.
If Vitamin B6 is also requested and there is only one tube, please split before freezing and sending.