Hypertension during Pregnancy: Test and Diagnosis

Laboratory parameters of the 1st order – obligatory laboratory tests.

  • Small blood count [hematocrit ↑, platelets ↓]
  • Inflammatory parameters – CRP (C-reactive protein) [HELLP syndrome: detectable in up to 62% of cases and not a result of infection]
  • Urine status including sediment, if necessary urine culture (pathogen detection and resistogram, that is, testing of suitable antibiotics for sensitivity / resistance) and detection of protein (detection of protein)* [pathological: ≥ 300 mg/24 hours protein].
  • Electrolytes – sodium, potassium
  • Renal parameters – urea, creatinine, cystatin C or creatinine clearance if necessary [creatinine: ≥ 0.9 mg/dl = 79.56 μmol/l].
  • Uric acid [> 5.9 mg/dl = 350 μmol/l]
  • Liver parameters – alanine aminotransferase (ALT, GPT), aspartate aminotransferase (AST, GOT), glutamate dehydrogenase (GLDH) and gamma-glutamyl transferase (gamma-GT, GGT), alkaline phosphatase, bilirubin [bilirubin ↑ (indirect: > 1.2 mg/dl = > 20.5 μmol/l), GOT ↑, GPT ↑]
  • LDH (lactate dehydrogenase) – hemolysis parameter/primarily used to differentiate anemia (anemia) or in cardiomyopathies (heart muscle disease) [LDH ↑]
  • Coagulation parameters – PTT, Quick, antithrombin III (AT-III), D-dimer, fibrinogen, etc. [Quick ↓, PTT ↑, AT-III ↓, fibrinogen ↓]

Laboratory parameters 2nd order – depending on the results of the history, physical examination, etc. – for differential diagnostic clarification.

  • Haptoglobin (hemolytic disease: disease associated with dissolution of red blood cells, erythrocytes) [decreased in 95-97% of pregnant women; most sensitive parameter of hemolysis].
    • Other hemolysis parameters include:
      • Detection of fragmentocytes in peripheral blood smear (54 to 86%).
      • Total bilirubin increased (47-62%)
  • Antiphospholipid antibodies – in severe PE/HELLP syndrome before 34 weeks gestation and marked intrauterine growth regression (IUGR).
  • Growth factor “placenta growth factor (PIGF) – new biomarker to diagnose “placental preeclampsia” [increases in normal pregnancy until 33 weeks gestation].

Notice. * The severity of proteinuria (increased excretion of protein in the urine) does not determine the morbidity (incidence of disease) of pregnant women. Proteinuria may be absent in up to 34% of cases of eclampsia and in 5-15% of cases of HELLP syndrome!

Preventive laboratory diagnostics

Preeclampsia screening

  • SFlt-1/PIGF quotient (sFlt-1: soluble fms-like tyrosine kinase-1; PlGF: placental growth factor; determination: in the 2nd and 3rd trimester/pregnancy trimester) [SFlt-1/PlGF quotient: < 38 can rule out the disease with a high degree of certainty for the next four weeks in pregnant women with suspected preeclampsia; elevated values are associated with a high risk of acute or impending preeclampsia] Consensus-based recommendation: screening with the sFlt-1/PIGF quotient in all pregnant women should not be performed because of the low prevalence (disease incidence) and only very low predictive rates.
  • Congo red detection in urine [“Congophilia” of urine → preeclampsia] sensitivity (percentage of diseased patients in whom the disease is detected by the use of the test, i.e., a positive test result occurs) 80.2 percent; specificity (probability that actually healthy people who do not have the disease in question are also detected as healthy in the test) 89.2 percent; negative predictive value was 92.1 percent and accuracy 86.7 percent.
  • Other biochemical risk markers: pregnancy-associated plasma protein A (PAPP-A), placental growth factor (PIGF).

Legend

  • SFlt-1: soluble FMS-like tyrosine kinase-1 (anti-angiogenic factor); initiates placental regression.
  • PIGF: Placental Growth Factor; promotes growth and development of the placenta.