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Serum Creatine Kinase Is an Unreliable Predictor of Ectopic Pregnancy
Author(s) -
Plewa Michael C.,
Ledrick David,
Buderer Nancy Fenn,
King Randall W.
Publication year - 1998
Publication title -
academic emergency medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.221
H-Index - 124
eISSN - 1553-2712
pISSN - 1069-6563
DOI - 10.1111/j.1553-2712.1998.tb02708.x
Subject(s) - medicine , ectopic pregnancy , miscarriage , pregnancy , obstetrics , creatine kinase , confidence interval , population , gynecology , genetics , environmental health , biology
Objective : To compare serum creatine kinase (CK) values in patients with ectopic pregnancy vs patients with threatened miscarriage or normal pregnancy. Methods : An observational case‐control study was performed at an urban teaching hospital. Pregnant women with a quantitative β‐hCG obtained for suspicion of ectopic pregnancy were evaluated. Excluded were cases with recent trauma, IM injections, surgery, or history of heart, liver, or muscle disease. The serum β‐hCG and CK values were recorded and compared between groups with 1‐way ANOVA and Tukey's multiple comparison procedure at the overall 0.05 level. Results : The 15 ectopic, 28 threatened miscarriage, and 21 normal pregnancy cases were of similar gestational ages (p = 0.2), ranging from 3 to 12 weeks. Although the CK values for ectopic pregnancy (88.8 ± 33.6 IU/L) exceeded those for threatened miscarriage (65.9 ± 59.0 IU/L) and normal pregnancy (56.0 ± 38.1 U/L) (p = 0.02), there was significant overlap between groups. CK values were at or above a cutoff of 74 IU/L in 80% (95% confidence interval: 52–96%) of ectopic pregnancies, 25% (11–45%) of threatened miscarriages, and 14% (3–36%) of normal pregnancies. Conclusions : Although the ectopic pregnancy population is characterized by a higher mean CK than are patients with threatened miscarriage or a normal pregnancy, a significant overlap in CK values makes use of this serum marker unreliable for detecting ectopic pregnancy.