IDENTIFYING OPERATIONAL ISSUESWITH
TOTAL B12 AND RESOLVING THEM BY
IMPLEMENTING ACTIVE B12
PLACE: FLINDERS MEDICAL CENTRE (FMC)
DEPARTMENT: AUTOMATED CORE LAB – BIOCHEMISTRY
DATE: 15.09.25 – 10.10.25 – 140HRS
BY : AROCKIA PETER FRANCIS
STUDENT: 11762771
Vitamin B12
2.
OVERVIEW
• IMPORTANCE OFVITAMIN B12 (COBALAMIN)
• MEASURING TOTAL B12
• CONCERNS WITH TOTAL B12
• OVERCOME BY ACTIVE B12
• ACTIVE B12 WORK-UPS
• IMPLEMENTED ACTIVE B12 TESTING (SA PATHOLOGY)
• CONCLUSION
• REFERENCES
3.
VITAMIN B12 (COBALAMIN)
Water-solublemicronutrient
Unable to synthesize by the body (Hannibel et al., 2009)
Carbohydrate, fat and protein metabolism
Nucleic acid synthesize
Act as a coenzyme for methionine synthase (MS) and methylmalonyl-CoA mutase (MCM), deficiency in B12
leads to accumulation of Homocystein and Methylmalonic acid.
Formation and regeneration of red blood cells
Deficiency:
Haematological disorder – megaloblastic anemia
Neurological disorders – demyelination and cognitive decline
Bone disorder and optic neuropathy – but less frequent
Causes:
Malabsorption due to pernicious anemia (autoimmune), aging, poor dietary intake
Genetic disorders
https://ods.od.nih.gov/factsheets/VitaminB12-HealthProfessional/
4.
MEASURING TOTAL B12
Themost direct assessment to determine Vitamin B12 status (Hannibel et al.,2016)
Widely available in clinical chemistry laboratories
Ranges:
normal (>250 pmol/L)
low (150–249 pmol/L)
acute deficiency (<149 pmol/L (Mirkazemi, C et al., 2012)
5.
CONCERNS WITH TOTALB12
Limitations:
1. This assay measures total circulating B12, of which
80% - bound to haptocorrin – not bioavailable for cell uptake
20% - bound to bioactive protein – holo-transcobalamin (Holo-TC) – available for cell uptake
The serum B12 does not represent the cellular B12 status (Lysne, V et al., 2016)
A patient with a genetic error for B12 metabolism can represent a normal to low total B12, but
actually be deficient in the cellular B12 level (Hannibel et al., 2016)
Total B12 assay is not a reliable biomarker for vitamin B12 status by itself (Hannibel et al.,2016)
6.
SOLUTION
By implementing activeB12 (Holo-TC)
Active B12 measures only vitamin B12 which were bound to Holo-TC.
After absorption, vitamin B12 binds to Holo-TC and is distributed to all the cells. Cells uptake Holo-TC
by the receptor called transcobalamin receptor (TCblR; CD320)(Quadros et al.,2009)
Holo-TC is the successive marker for bioactive Vitamin B12 (Noxo et al.,2000)
The normal range of holo-TC in healthy individuals is 20–125 pmol/L (Valente et al.,2011).
SA Pathology Interpretation
7.
ACTIVE B12 TESTIMPLEMENTATION PLAN AND STEPS
1. Preparation of the validation/Verification plan for active B12.
We started making a validation plan for FMC using template VAL-753
2. Preparation of FMC QC date
We downloaded active B12 into line 2 (Roche Cobas e602), calibrated and ran QC every day for 20 days.
3. Running correlation samples from RAH
RAH (Royal Adelaide Hospital) is the only lab currently running active B12 in SA pathology. So we requested
some active B12 patient samples for a correlation study.
4. Testing external QAP samples
We enrolled in the active B12 program on the RCPA QAP website.
Since we have already enrolled in special endocrine tests, such as PTH and Cortisol, we freeze the QAP samples
each month, and they remain stable for up to 12 months.
We retrieved those frozen samples, thawed them, and ran them for active B12.
8.
5. Running dilutionseries
A dilution series is conducted to demonstrate the linearity of an assay. Reading 1, 2, and 3 should be
performed on different days to account for data variability.
6. Functional sensitivity
A functional sensitivity (LoQ) is the lowest concentration at which the analyte can be reliably detected.
"Functional sensitivity” has been set to a predefined concentration that yields a coefficient of variation (CV)
of 20%.
7. Submitting data for approval
All workups have been submitted in Q Pulse for pathologist approval.
8. IT changes and trial run
Once approved, my supervisor contacted the IT team and scheduled a date for the IT changeover. The trial
patient was entered and checked for transferring results from the middleware to the LIS.
9. Sent email to lab staff
My supervisor sent a memo to all lab staff regarding the transition of the active B12 changeover.
10. Successful transition to active B12
9.
IMPLEMENTED ACTIVE B12IN SA PATHOLOGY
Communication was passed to all the staff for the changeover.
Change to B12 testing requests Trainer: Skye Rumbelow
Introduction/Description
Transition from Vitamin B12 testing to Holo-TC (Active B12)
on Roche Cobas e602
Applicability
FMC Core Lab - Biochemistry
New Test/Laboratory Change/Information
Holotranscobalamin (Active B12) is the biologically active
fraction of Vitamin B12 and it is proposed to be a more
diagnostically accurate and clinically relevant indicator of
vitamin B12 deficiency than total serum vitamin B12.
From the 1st
July 2025, the Department of Health amended
the MBS items for vitamin B12 testing (66838 and 66839)
and created a new item for vitamin B12 testing (66842).
To reduce costs and provide the most clinically relevant
results for our patients SA Pathology is transitioning to
testing Holo-TC (active B12) only. Total B12 testing will
continue to be offered only at the RAH on the e801 platform
for specific patients with inborn errors of metabolism.
Given the higher cost of Holo-TC testing, testing will be
consolidated to the following laboratories: RAH, FMC,
LMH, Mount Gambier, Modbury, tQEH and Noarlunga.
Reagent: Roche Active B12
Storage: Cold Room 2 (4°)
Dr Jill Lipsett
Clinical Service Director
SA Pathology
10.
OTHER LIMITATIONS ANDSOLUTIONS
2. Time-consuming:
Roche COBAS test inserts,
Total B12 - 28 mins
Active B12 – 18 mins
3. Sustainability:
Total B12 – 2 separate cassettes (pre-treatment and testing)
Active B12 – 1 cassette
Less waste
4. Stability:
Onboard stability
Total B12 – 35 days
Active B12- 48 days
Reagent packs: Left- Total B12, Right – Active B12
11.
CONCLUSION
Vitamin B12 -A very essential water-soluble micronutrient
Total vitamin B12 measurement is a widely available assay for vitamin B12 status.
Limitation: overall circulating Vitamin B12, but not the cellular availability level.
Solution: Active B12 (Holo-TC) provides a clinically reliable interpretation for vitamin B12
deficiency.
FMC validation of active B12 has been successfully conducted (QC, Correlation tests, Dilution
assay, Sensitivity tests, RCPA QAP samples) and passed in all.
OUR NEXT GOAL, UNDER CONSTRUCTION NOW……
After implementing active B12, the next stage of progress for this analyte will be adding a
reflex homocysteine test for active B12-deficient patients (<25 pmol/L).
12.
REFERENCE
Green R., AllenL. H., Bjørke-Monsen A. L., Brito A., Guéant J.-L., Miller J. W., Molloy A. M., Nexo E., Stabler S., Toh B.-H., Ueland P. M., and Yajnik C. (2017).
Vitamin B12 deficiency, Nature Reviews Disease Primers, 3, no. 1, article 17040, https://doi.org/10.1038/nrdp.2017.40, 2-s2.0-85021656925.
Greibe E, Andreasen BH, Lildballe DL, et al. Uptake of cobalamin and markers of cobalamin status: a longitudinal study of healthy pregnant women. Clin Chem Lab
Med 2011;49:1877-1882.
Hannibal, L., Lysne, V., Behringer, S., Grünert, S. C., Spiekerkoetter, U., Jacobsen, D. W., & Blom, H. J. (2016). Biomarkers and Algorithms for the Diagnosis of
Vitamin B12 Deficiency. Frontiers in Molecular Biosciences, 3, 205004. https://doi.org/10.3389/fmolb.2016.00027
Harrington, D. J. (2018). Methods for assessment of Vitamin B12. Laboratory Assessment of Vitamin Status, 265-299.
https://doi.org/10.1016/B978-0-12-813050-6.00012-7
Lysne, V., Strand, E., Svingen, G. F. T., Bjørndal, B., Pedersen, E. R., Midttun, Ø., et al. (2016). Peroxisome proliferator-activated receptor activation is associated
with altered plasma one-carbon metabolites and B-vitamin status in rats. Nutrients 8:26. doi: 10.3390/nu8010026
Mirkazemi, C., Peterson, G. M., Tenni, P. C., and Jackson, S. L. (2012). Vitamin B12 deficiency in Australian residential aged care facilities. J. Nutr. Health Aging 16,
277–280. doi: 10.1007/s12603-011-0348-2
Nexo, E., Christensen, A. L., Petersen, T. E., and Fedosov, S. N. (2000). Measurement of transcobalamin by ELISA. Clin. Chem. 46, 1643–1649.
Quadros, E. V., Nakayama, Y., and Sequeira, J. M. (2009). The protein and the gene encoding the receptor for the cellular uptake of transcobalamin-bound
cobalamin. Blood 113, 186–192. doi: 10.1182/blood-2008-05-158949
Solomon, L. R. (2015). Functional cobalamin (vitamin B12) deficiency: role of advanced age and disorders associated with increased oxidative stress. Eur. J. Clin.
Nutr. 69, 687–692. doi: 10.1038/ejcn.2014.272
Stabler S. P., Vitamin B12 deficiency, The New England Journal of Medicine. (2013) 368, no. 2, 149-160, https://doi.org/10.1056/NEJMcp1113996, 2-s2.0-
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Valente, E., Scott, J. M., Ueland, P. M., Cunningham, C., Casey, M., and Molloy, A. M. (2011). Diagnostic accuracy of holotranscobalamin, methylmalonic acid,
serum cobalamin, and other indicators of tissue vitamin B(1)(2) status in older people. Clin. Chem. 57, 856–863. doi: 10.1373/clinchem.2010.158154
#3 Humans are unable to synthesize B12 and thus rely on dietary intakes.
Deficiency in vitamin B12 can have major clinical implications and cause
irreversible damage if left untreated. The most common manifestations
of vitamin B12 deficiency
#4 The most direct assessment and perhaps preferred first-assay to determine vitamin B12 status is the measurement of total serum vitamin B12. This assay is widely available in clinical chemistry laboratories.