INFLUENCE OF HEPARIN ON ELECTROLYTES ANALYSED ON ELECTROLYTE ANALYSER IN AN EMERGENCY BIOCHEMISTRY LABORATORY OF PGIMS ROHTAK – A COMPARATIVE STUDY WITH SERUM

Sabiha Naz*, Kiran Chugh and Isha Malik

ABSTRACT

Background: Serum electrolytes (Sodium and Potassium) are conventionally measured in all critical patients of emergency department, patients receiving fluid therapy and those admitted to intensive care units. The electrolytes concentration can be measured by an electrolyte analyser in heparinised blood as well as in serum. Our present study is designed in order to find out the effect of heparin on electrolytes (sodium and potassium) in heparinised blood and to compare the heparinised blood electrolyte measurements and serum electrolyte measurements in same patient’s sample. Methods: This is a prospective observational study conducted in the emergency laboratory of Biochemistry Department at Pt.B.D.Sharma PGIMS, Rohtak. We obtained coupled samples, one heparinised blood sample and other venous sample (for serum) from 150 patients admitted in the accidental and emergency department, intensive care units and different wards of Pt.B.D.Sharma PGIMS, Rohtak. We analyzed both of them on Eschweiler Combiline Electrolyte Analyser based on Direct ISE Method. The results obtained were uploaded to MS excel sheets and further divided into 3 groups viz Group I (having a very low variation in electrolyte values between heparinised blood and serum), Group II (having moderate variation in electrolyte values between heparinised blood and serum), and Group III (having high variation in electrolyte values between heparinised blood and serum).Statistical analysis was done using students unpaired ‘t’ test. Results: In Group I, the mean sodium value in heparinised blood was 136.28 ±7.39 mmol/ L and mean sodium value in serum was 136.88 ±7.42 mmol/L(p value>0.05). In Group II ,the mean sodium value in heparinised blood was 134.01 ±7.72 mmol/ L and mean sodium value in serum was 136.93 ±7.62 mmol/L(p value<0.05) and In Group III, the mean sodium value in heparinised blood was 133.92 ±7.21 mmol/ L and mean sodium value in serum was 143.12 ±7.39 mmol/L(p value<0.001). Similarly, In Group I, the mean potassium value in heparinised blood was 4.22 ±0.85 mmol/ L and mean potassium value in serum was 4.29 ±0.83 mmol/L (p value>0.05). In Group II, the mean potassium value in heparinised blood was 4.21 ±0.91 mmol/ L and mean potassium value in serum was 4.58 ±0.85 mmol/L(p value<0.05) and In Group III ,the mean potassium value in heparinised blood was 3.69 ±0.93 mmol/ L and mean potassium value in serum was 4.65 ±0.90 mmol/L(p value<0.001). Conclusion: We concluded that serum electrolytes values in heparinised blood and serum were having statistical insignificant (p>0.05) difference in Group I while we obtained statistical significant (p<0.05) as well as statistical highly significant (p<0.001) difference in Group II and Group III respectively. These above stated significant differences may be due to improper dilution of blood sample with heparin. If heparin is used in proper quantity (i.e 50-80 IU/ml vol. of blood) correct and comparable results may be obtained on which critical clinical decisions can be made by trusting the electrolytes values obtained through heparinised blood testing on electrolyte analyser.

Keywords: Electrolytes, Heparin, Sodium and Potassium.