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Sensitive and Specific Findings

Sensitive Findings

Findings With Unspecified Accuracy

Premature Rupture of Membranes: Sensitivity and Specificity

Introduction: None written.

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The sensitivity and specificity of findings for Premature Rupture of Membranes are listed below. See the left navigation bar to change the display.

Pre-Test Probability (Prevalence): %.	Post-Test Probability (Predictive Value): %.	Switch to display mode.
Note that calculating probabilities from more than one** finding is inherently inaccurate because findings are not independent. (For example, using two positive findings that share a common pathogenesis is likely to overestimate the true probability.)

Sensitive and Specific Findings
Finding	Result	Sensitivity	Specificity
[ + ] Ferning of Vaginal Fluid	+ 0 -	96%	100%
'ferning' refers to formation of crystals as the fluid dries (in a palm-leaf pattern). Note that cervical mucus itself will display ferning but the pattern is much thicker than that from amniotic fluid. Study: Am J Perinatol. 1990 Jul;7(3):276-8 PMID: 1695510
[ + ] Fat Droplets in Fluid	+ 0 -	99.3%	97.2%
seen by sudan black staining. Not present before term! Study: Clin Obstet Gynecol. 1991 Dec;34(4):715-22 PMID: 1778013
[ + ] AFP in Vaginal Fluid	+ 0 -	91%	95%
Study: Am J Perinatol. 1990 Jul;7(3):276-8 PMID: 1695510

Sensitive Findings
Finding	Result	Sensitivity	Specificity
[ + ] Nitrazine pH Indicator of Fluid	+ 0 -	91%	73%
alkaline pH causes a change to blue, implying that it is of amniotic origin Other studies have found specificity up to 96%. Study: Am J Perinatol. 1990 Jul;7(3):276-8 PMID: 1695510 Clin Obstet Gynecol. 1991 Dec;34(4):715-22 PMID: 1778013

Findings With Unspecified Accuracy
Finding	Result	Sensitivity	Specificity
[ + ] History		No accuracy specified.
"history has an accuracy of 90%" (unable to get original study since it's so old) Patients may describe either a gush of fluid or a slow trickle Study: Clin Obstet Gynecol. 1991 Dec;34(4):715-22 PMID: 1778013