Podcast 858: Whole Blood Pregnancy Test

Contributor: Meghan Hurley MD

Educational Pearls:

What do you do if you need a stat pregnancy test on an incapacitated patient?

• You can send a serum quantitative human chorionic gonadotropin (beta-HCG), but that might take a while for the lab to process.

• Another option is to place a drop of whole blood on a urine pregnancy immunoassay.

• These tests are already verified for urine and serum.

• 2012 study showed that whole blood was 95.8% sensitive for pregnancy compared to 95.3% for urine.

• Takes a little bit longer (10 minutes was used in the study) due to the viscosity of blood.

• Word of caution: This study only looked at a single urine pregnancy kit type. It is possible that other kits would have a different efficacy.

• There are new finger stick tests coming out for capillary blood.

• Anecdotally, Dr. Hurley was able to use this technique to support a diagnosis of ruptured ectopic pregnancy in a patient that needed emergent surgery.

References

• Fromm C, Likourezos A, Haines L, Khan AN, Williams J, Berezow J. Substituting whole blood for urine in a bedside pregnancy test. J Emerg Med. 2012 Sep;43(3):478-82. doi: 10.1016/j.jemermed.2011.05.028. Epub 2011 Aug 27. PMID: 21875776.

• Sowder AM, Yarbrough ML, Nerenz RD, Mitsios JV, Mortensen R, Gronowski AM, Grenache DG. Analytical performance evaluation of the i-STAT Total β-human chorionic gonadotropin immunoassay. Clin Chim Acta. 2015 Jun 15;446:165-70. doi: 10.1016/j.cca.2015.04.025. Epub 2015 Apr 25. PMID: 25916696.

Summarized by Jeffrey Olson, MS1 | Edited by Meg Joyce & Jorge Chalit, OMSII