Analysis of Prescribed Critical Values in Istanbul Training and Research Hospital Biochemistry Laboratory: Should Critical Values Be Repeated?

Clinically important critical values must be readily available to the clinician. Repeating critical values may cause a delay. In this study, we evaluated the requirement of repeating critical values.

We extracted initial and repeated critical values and reporting times for a six-month period via the hospital laboratory information management system. Ten parameters from our critical value list (glucose, urea, mag-nesium (Mg++), calcium (Ca++), sodium (Na+), potassium (K+), chloride (Cl-), white blood cells (WBC), platelets, hemoglobin) were evaluated. We assessed whether the difference between the first measurement of the initial critical value and the repeated measurement value exceeded total allowable error (TEa).

Repeated critical values of Mg++, Ca++, WBC, platelets, and hemoglobin did not exceed TEa. However, repeated critical values of glucose, urea, Na+, K+, and Cl- did exceed TEa. In addition, parameters such as glucose and urea did not affect the clinical decision although their critical values exceeded the TEa. This study showed that critical values for Na+, K+, and Cl- may need to be repeated.

Each laboratory should assess the requirement of repeating critical values under its own operating conditions and, accordingly, establish and implement a suitable policy.