Validity Of Point of Care Pregnancy Testing in the ED

Using Serum From Whole Blood Collected At Bedside

Linh T Le, M.D. PGY IIIDivision of Emergency Medicine

Saint Louis University, School of Medicine

Disclaimer

• We would like to thank Sekisui Diagnostics for their donation of the pregnancy test assays.

• There was no monetary funding from the company for the study.

Study TeamAuthors and Co-Investigators• Preeti Dalawari, MD, MSPH• Kamal Gursahani, MD, MBA• Eric Lee, MD• Katrina Wade, MD

We would like to acknowledge:• ED nursing staff, attendings, residents and

medical students

Background• POCT urine pregnancy

Most common practiceUrine can be unobtainable, take time

• Serum hCG laboratory test Increased costProlonged time

• POCT serum pregnancy Easy to performMay be faster in certain situationsNOT a CLIA waive test

Study Objectives1. Demonstrate validity of POCT serum

pregnancy to the current standard of care:

• POCT urine pregnancy test • Serum hCG qualitative/quantitative laboratory

test• Obvious ultrasound evidence of IUP

2. Compare the tests metrics to see if there is a difference

Hypotheses1. We hypothesized that POCT serum

pregnancy test can be as reliable as the POCT urine pregnancy test and serum hCG laboratory test.

2. We also hypothesized that POCT serum pregnancy test may be more efficient in certain clinical scenarios

Study Design• IRB approved, single site cross sectional study

at Saint Louis University Hospital

• All enrolled patients signed informed consent and HIPPA forms

• All of the samples were tested via POCT serum (study test) and a standard of care test

Study Design Blood sample obtained from patient in a tube with no

anticoagulants/additives Sample was placed up right allow to separate by

gravity for >20 mins Both the POCT urine and serum samples were

applied to the OSOM hCG Combo Test• Sensitivity

› 20 mIU/mL Urine› 10 mIU/mL Serum

• Timing› 3 minutes for urine› 5 minutes for serum

Study Design• Estimated pregnancy prevalence of 8%

in the study population

• A sample size of 210 subjects is needed to achieve 80% power at a 5% alpha level using a two-sided equivalence test of correlated proportions

Preliminary Results 76 patients enrolled thus far

Mean age: 28.4

Standard deviation 7.5

22% of the patients were pregnant.

Preliminary ResultsPOCT serum compared to POCT urine

100% sensitivity and 100% specificity

POCT serum compared to laboratory serum hCG100% sensitivity and 100% specificity

POCT serum compared to bedside ultrasound

100% sensitivity and 100% specificity

Preliminary ResultsTime of test order to time of results• POCT urine

– Average time: 51 minutes– Standard deviation: 42 minutes

• POCT serum– Average time: 97 minutes– Standard deviation: 47 minutes

Limitations

May not be true representation of the ED care timeline as consent has be to obtained prior to using patient’s already collected blood – this may increased the “order to result” time for POCT serum test

Limitations

Limited by using only the OSOM hCG Combo Test, it is possible that different

manufacturer’s assays may have different results

Conclusion

POCT pregnancy test using OSOM hCG Combo Test can be done reliably using

serum blood at the bedside

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