Laboratory parameters of the 1st order – obligatory laboratory tests.
There are no specific laboratory tests that must be performed as part of the diagnosis of cervical insufficiency. The only concern is to rule out infections.
- The following tests should be performed to rule out vaginal inflammation:
- Bacteriological smear if colpitis (vaginitis)/cervicitis (cervicitis) is suspected.
- Fluorine diagnostics (discharge diagnostics) in the native preparation (fresh, unfixed preparation for microscopic examination) [bacteria, lymphocytes].
- Measurement of the pH of the vaginal secretion / vaginal secretion [alkaline?]
- To rule out systemic inflammation, the following tests (inflammatory parameters) should be performed:
- ESR (erythrocyte sedimentation rate)
- CRP (C-reactive protein)
- Leukocytes
- To exclude a urinary tract infection than the following tests should be performed:
- Sediment
- Urine strip test bacteriological examination if necessary.
Laboratory parameters 2nd order – for differential diagnostic clarification of a possible impending premature birth or premature rupture of the membranes.
- Fibronectin test (biochemical marker of cervical ripening). It is used to predict impending preterm delivery. If the test is negative for clinical signs of impending preterm birth, it can be stated with a certainty of about 99% that no birth will occur within the next 14 days. This can avoid hospitalization, pulmonary ripening induction with corticosteroids, and any planned tocolytic therapy (labor inhibition). While a positive test may be coupled with an increased risk of preterm delivery, prediction is uncertain. Fetal (infant) fibronectin from vaginal secretions is measured. The test can be performed during the 22-35th SSW. If the pregnancy is intact, fetal (fetal) fibronectin should not be secreted during this time.
- Amniotic fluid testing (biochemical test for amniotic fluid proteins to verify premature rupture of the bladder). Amniotic fluid proteins detectable in vaginal secretions after premature rupture of the membranes are measured. The following methods are available for this purpose:
- Actim Partus: The method represents a one-step membrane immunoassay that can detect highly specific phosphorylated insulin-like growth factor binding protein-1 (phIGFBP-1) from cervical smears by using two monoclonal antibodies. The phIGFBP-1 is a protein released by the decidua cells (nutrient-rich cell of the endometrium; decidua cells contain glycogen (multisugars composed of glucose units), and can be detected in cervical secretions shortly before birth. The increased release of the protein is due to the detachment of the egg membranes from the decidua, allowing phIGFBP-1 to enter the cervical secretion. According to the manufacturer’s instructions, a positive test result is present at a concentration of 10 µg/l of phosphorylated IGFBP-1.
- Actim PROM Test (PROM, Premature Rupture of Membranes): the detection of premature rupture of membranes is based on the use of monoclonal antibodies that precisely detect non-phosphorylated Insulin-like Growth Factor Binding Protein-1 (IGFBP-1). Protein detection can be used to qualitatively determine amniotic fluid in the vagina (vaginal) by rapid test. The benefit of Actim PROM lies in particular in the high specificity of the diagnostic procedure, since the detection of IGFBP-1 in the smear is to be regarded as a sure sign of the presence of ruptures in the embryonic membrane. The appearance of IGFBP-1 in the smear preparation is possible only if a significant amount of amniotic fluid enters the vagina, which occurs in the event of rupture of the bladder.
Determining whether there is a premature rupture of the membranes can be very difficult in individual cases, but is clinically relevant. Because in cases of preterm labor and premature rupture of the membranes, the administration of antibiotics is indicated. They lead to a reduction in amniotic infection syndrome (AIS: infection of the egg cavity, placenta, membranes and possibly the fetus/unborn child during pregnancy or birth with risk of sepsis (blood poisoning) for the child) and the preterm birth rate.If there is only preterm labor or cervical insufficiency, antibiotics are generally not indicated unless there is a vaginal infection.
