PROBLEM: To assess the usefulness of amniotic fluid (AF) granulocyte colony stimulating factor (G-CSF) levels as a rapid marker for diagnosing chorioamnionitis.
METHOD OF STUDY: AF levels were obtained from term and preterm patients with and without chorioamnionitis (CAM). Patients with urinary tract, respiratory tract, and other infections were excluded. Results obtained from the AF G-CSF assays were compared with those from other parameters used for diagnosing CAM: maternal fever, leukocytosis, tachycardia, fetal tachycardia, AF glucose levels, white blood cell count, Gram stain, and aerobic and anaerobic cultures. The sensitivity, specificity, and predictive values were calculated.
RESULTS: In the uninfected AF samples, G-CSF levels were present but low, ranging from 400 to 1600 pg/ml. Levels in the infected samples, however, were markedly increased, ranging from 1600 to 14,000 pg/ml; P < 0.05. When a cutoff of 2000 pg/ml was used as a clear marker for CAM, the sensitivity was 67%, the specificity was 100%, and the positive and negative predictive values were 100% and 86%, respectively. The comparison of the other AF G-CSF laboratory parameters also revealed high sensitivity, specificity, and predictive values for detecting CAM.
CONCLUSION: (i) AF G-CSF levels are elevated in CAM. (ii) An AF G-CSF level >2000 pg/ml is a strong positive predictor of CAM. (iii) Elevated AF G-CSF levels appear to be more reliable in predicting CAM than any other single test currently used in clinical practice.