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Estimation of total and direct serum bilirubin using modified micro assay method
Afsheen Aman1, Shah Ali Ul Qader, Saeeda Bano
1Pharmaceutical Research Center, PCSIR Laboratories Complex, Karachi, Pakistan.
The Italian Journal of Biochemistry
|August 29, 2007
Summary
A new micro assay method significantly reduces serum sample volume for bilirubin testing, proving reliable for infants and various analyzers. This method accurately estimates total and direct bilirubin using minimal blood samples.
Area of Science:
- Clinical Chemistry
- Neonatal Medicine
Background:
- Accurate bilirubin estimation is crucial for diagnosing hyperbilirubinemia, especially in neonates.
- Existing spectrophotometric methods require large serum volumes (200-800 ml), posing challenges for infant blood collection.
- Neonatal jaundice is a common issue, necessitating methods with minimal sample requirements.
Purpose of the Study:
- To develop and validate a modified micro assay method for estimating total and direct bilirubin.
- To reduce the required serum sample volume for bilirubin assays.
- To assess the reliability of the micro assay method for clinical use, particularly in infants.
Main Methods:
- A modified micro assay using dimethylsulfoxide (DMSO) was developed to decrease serum sample volume to 20 ml per test.
- Method comparison was conducted using 100 serum samples against the Jendrassik-Grof reference method.
- Assay performance was evaluated for linearity, correlation, and stability.
Main Results:
- The modified micro assay demonstrated high correlation with the Jendrassik-Grof method (r=0.99989 for total bilirubin, r=0.99971 for direct bilirubin).
- The method exhibited linearity up to 20 mg/dl for total bilirubin and 15 mg/dl for direct bilirubin.
- The assay is rapid, reliable, simple, and accurate, requiring only small serum quantities.
Conclusions:
- The modified micro assay method is a viable alternative for accurate bilirubin estimation, especially when serum volume is limited.
- This method is suitable for use with manual, semi-automated, and automated chemistry analyzers.
- The micro assay method offers a practical solution for diagnosing hyperbilirubinemia in infants and other patient populations requiring minimal blood draws.
