Urinary dipstick proteinuria testing: does automated strip analysis offer an advantage over visual testing?

Area of Science:

• Clinical Chemistry
• Maternal Health
• Diagnostic Accuracy

Background:

• Proteinuria is a key indicator of preeclampsia in pregnancy.
• Accurate and timely screening for proteinuria is crucial for maternal and fetal outcomes.
• Urine dipstick tests are commonly used for proteinuria screening, with both visual and automated reading methods available.

Purpose of the Study:

• To compare the diagnostic performance of automated versus visually read urine dipstick tests.
• To evaluate the detection of a random protein:creatinine ratio (PrCr) ≥ 30 mg/mmol.
• To assess screening accuracy in pregnant women in a high-risk maternity clinic setting.

Main Methods:

• Prospective collection of urine samples from 160 pregnant women.
• Division of samples into aliquots for visual and automated dipstick testing.
• Comparison of dipstick results (proteinuria ≥ 1+) against a reference standard of PrCr ≥ 30 mg/mmol using non-dilute samples.

Main Results:

• Both visual and automated dipstick tests demonstrated low sensitivity (56.0% and 53.8%, respectively).
• Positive likelihood ratios were 15.0 (visual) and 24.6 (automated).
• Negative likelihood ratios were 0.46 (visual) and 0.47 (automated).

Conclusions:

• Automated dipstick testing offers no significant advantage over visual testing for proteinuria detection in this pregnant cohort.
• The sensitivity of dipstick tests may be influenced by the specific test strips and automated readers used.
• Further research is needed to optimize dipstick performance for proteinuria screening in pregnancy.