How Long can we Store Blood Samples: A Systematic Review and Meta-Analysis

Highlights

• For CMP, > 12 h. storage generate unreliable results.

• For CBC, samples could reliably be stored for 24 h.

• For longer storage, 4 °C would be a better choice.

Blood tests are the most common laboratory tests giving basic and valuable information. But in most cases, we cannot analysis immediately, so how and how long can we keep samples to get reliable results need to be known for both laboratory staffs and clinicians. As shown in our results, complete blood count results are more stable than comprehensive metabolic panel testing and can get reliable results even 24 h. storage; the advantages of refrigerator store (4 °C) are clear for longer storage. We think this could help standardize blood samples storage and get reliable test results.

Abstract

Objective

To assess the effect of storage time and temperature on complete blood count (CBC) and comprehensive metabolic panel (CMP) testing.

Methods

PubMed, EMBASE, the Cochrane Library of Systematic Reviews, Web of Science (WOS), China National Knowledge Infrastructure (CNKI), WanFang databases and SinoMed databases were searched up to May 2017. Clinical trials with adult whole blood samples were identified. Paired reviewers independently screened, extracted data and evaluated the quality of evidence (MINORS tool). Analyses were conducted using Revman 5.3 and Stata 14.0.

Results

A total of 89 studies were confirmed. For CBC, except MPV, most parameters were stable at least for 24 h. Some indices, such as WBC, PLt, HCT, HGB and MCH were stable up to 3 d. However, stable CMP test results could only be acquired within 12 h. at 4 °C, including GLU, AST, ALT, Na, ALB, Cl, DBIL, TC, TG and ALP. Values were less stable when stored at RT.

Conclusions

Specimens stored > 12 h. for CMP may generate unreliable results. For CBC, samples could reliably be stored for 24 h. For longer storage, refrigeration (at 4 °C) would be a better choice.