Currently, the standard workup and therapeutic monitoring of PE include limited laboratory testing. The following laboratory tests can be employed to assist in the diagnosis of PE, establish baseline levels early in the disorder, and monitor for progression to HELLP or severe preeclampsia:
Urine Assays
A 24-hour urine collection for protein determination should be obtained whenever possible to diagnose proteinuria. If a 24-hour urine collection is not possible, a urine dipstick analysis on a random sample may be used to help make the diagnosis of proteinuria. The severity of the proteinuria may be helpful in determining if the PE is mild or severe, as described previously.
In addition, random urine samples may be analyzed for both protein and creatinine levels and used to calculate the protein-to-creatinine ratio (P/C). Although a P/C ratio of greater than 0.3 may suggest proteinuria, there is no clinically acceptable agreement on the best P/C threshold level for categorizing pregnant women with significant proteinuria.
One of the earliest laboratory manifestations of PE is the presence of hyperuricemia. Serial levels of urine uric acid may be useful to indicate the disease progression.
Serum Chemistries
To further assist in the diagnosis of the HELLP syndrome, serum levels of LDH, AST, bilirubin, and ALT are assessed to identify possible hemolysis and abnormal liver function. Increases in AST and ALT may indicate liver involvement, and increases in bilirubin and LDH may suggest hemolysis.
