Critical limits for urgent clinician notification at South African intensive care units

Background: Critical value policies are used by clinical laboratories to decide when to notify caregivers of life-threatening results. There, however, remains much debate regarding which tests should be included in critical value lists and clinically relevant limits. Method: An electronic survey was designed to determine the critical value policies of specialists for haematology tests in South African intensive care units. Data collected included a demographic component, critical value policies and critical value reporting. Results: There were 68 respondents who represented a range of specialists from different disciplines. Four key critical values were identified, namely white cell count (WCC), haemoglobin, platelet count and international normalised ratio (INR). Median low and high adult and paediatric critical limits for the most frequently listed tests were as follows: haemoglobin <7 and >20 g/dL, platelet count <50 and >1000 9 10(9)/L, WCC < 2 and >20 x 10(9)/L and INR > 4. Specific critical limits for neonates were reported by 20 of the respondents. Of the respondents, 95.92% indicated that it was important to be contacted with first-time critical results and approximately half for repeat critical values. The majority preferred that the person notified of the critical value be the caregiver directly involved with the patient's care. Conclusion: It is important for critical value policies to be reviewed by each discipline to ensure cut-offs are clinically relevant.