Search strategy and evidence selection

Search strategy and evidence selection

Search strategy

1. The following databases were searched using the keyword 'Active‑B12': Ovid Embase (between 1974 and 2015), Ovid MEDLINE(R) (between 1946 to April Week 3 2015), Ovid MEDLINE(R) In‑Process & Other Non‑Indexed Citations (up to April 22, 2015), CAB Abstracts (up to April 22 2015); Web of Science Core Collection (up to April 22 2015), and Scopus (up to April 22 2015).

2. Reference lists of identified studies were checked to identify any further studies.

3. Information provided by the manufacturer for supporting this briefing report was also checked to identify any further studies.

4. The internet was searched using the above keywords.

5., WHO ICTRP, and Current Controlled Trials were also searched for ongoing trials.

6. The manufacturer's website was thoroughly investigated.

Evidence selection

The inclusion criteria were as follows:

Patients: people for whom tests for vitamin B12 deficiency are needed.

Intervention: Active‑B12 assay being used on Abbott ARCHITECT i2000SR or i1000SR analyser for testing holotranscobalamin concentration in serum and plasma.

Comparator: any other assay for testing holoTC or tests for vitamin B12 deficiency level in blood.

Outcomes: any clinical, safety and resource use outcomes, including the following:

  • diagnostic test characteristics

  • the association between holoTC level and other measures of vitamin B12 status

  • assay throughput

  • time to test results

  • laboratory factors including workforce.

Study design: clinical studies including controlled and observational studies were included. Systematic reviews and meta‑analyses were used for identifying relevant primary studies only. Proof of concept and non‑English language studies were excluded.