Background: To determine the prevalence of subacute combined degeneration (SCD) patients with normal or elevated serum vitamin B-12 level and to identify clinical characteristics of these patients. Methods: We searched PubMed, EMBASE, and Cochrane library, without language restriction up to June 2019 and included studies with SCD patients who were diagnosed with normal or elevated serum vitamin B-12 levels. Meta-analysis was performed to estimate the prevalence of SCD in patients with normal or elevated serum vitamin B-12 levels and compare the differences of clinical data between patients with low and no-low serum vitamin B-12 level. Results: Six studies were included in our analysis, with a total number of 181 patients involved. The pooled proportion in patients with no-low serum vitamin B-12 level was 31.0% (95% confidence interval [CI]: 22.5-40.8). There was no significant difference in the level of hemoglobin (Mean difference (MD): -3.05, 95% CI: -12.42 to 6.33. P = 0.52) and erythrocyte mean corpuscular volume (MD: -2.37, 95% CI: -11.17 to 6.43, P = 0.60) between SCD patients with no-low and those with low serum vitamin B-12 levels. The meta-analysis showed that the functional disability rating scale on admission in patients with low serum vitamin B-12 level was no worse than that with normal or elevated serum vitamin B-12 level (MD: 0.29, 95% CI: -0.58 to 1.16, P = 0.51). Conclusion: Decreased level of serum vitamin B-12 may not be a necessity for the diagnosis of SCD. Approximately one third of the SCD patients have normal or elevated serum vitamin B-12 level. No differences were found in clinical severity between patients with normal or elevated serum vitamin B-12 level and those with low level of serum vitamin B-12 on admission.