Table 2.

Level 3 evidence—alert thresholds from surveys of laboratories or clinicians.a

Analytes, conventional units3b. Clinicians3c. Laboratory
Low threshold, median (range) [n]High threshold, median (range) [n]Low threshold, median (range) [n]High threshold, median (range) [n]
Potassium, mmol/L2.5 (2.5–2.5) [1]6.0 (6.0–6.0) [1]2.8 (2.6–2.9) [11]6.2 (6.0–6.5) [11]
Sodium, mmol/L120 (120–120) [1]160 (160–160) [1]120 (120–125) [10]159 (155–160) [10]
Glucose, mg/dL45.1 (45.1–45.1) [1]541 (541–541) [1]45.1 (39.6–50.1) [9]418 (360–485) [9]
Calcium, mg/dL5.2 (5.2–5.2) [1]15.2 (15.2–15.2) [1]6.4 (5.6–7.1) [11]12.9 (12.0–14.0) [11]
Hemoglobin, g/dL9.0 (9.0–9.0) [1]6.75 (5.3–7.5) [8]20.0 (18.4–20.0) [8]
Platelets, ×103/μL40 (30–50) [8]999 (700–1000) [8]
Magnesium, mg/dL0.97 (0.97–0.97) [1]1.1 (0.80–1.2) [8]4.9 (4.1–7.9) [8]
Phosphorus, mg/dL0.77 (0.77–0.77) [1]1.2 (0.99–1.2) [8]8.7 (8.0–9.3) [7]
WBC,b count/μL2,000 (2,000–2,000) [6]33500 (25000–46000) [6]
APTT, s19 (18–20) [3]87.5 (68–110) [8]
Creatinine, mg/dL0.20 (0.18–0.31) [4]5.2 (3.4–7.6) [9]
Urea, mg/dL4.6 (3.1–11.2) [4]87.7 (75.6–213) [9]
pH6.90 (6.90–6.90) [1]7.70 (7.70–7.70) [1]7.205 (7.20–7.44) [4]7.595 (7.55–7.60) [4]
INR5.5 (5.0–6.0) [2]
Fibrinogen, mg/dL100 (88–100) [3]787.5 (775–800) [2]
Po2, mmHg35 (35–35) [1]43.5 (40–60) [4]102 (93–111) [2]
Digoxin, ng/mL2.3 (2.0–3.0) [3]
Bicarbonate, mmol/L10 (10–10) [1]11 (10–15) [6]40 (39–40) [6]
Hematocrit, %20 (18–24) [3]60 (60–61) [3]
Pco2, mmHg20 (19–20) [3]68 (60–70) [4]
Ionized calcium, mg/dL2.4 (2.4–2.4) [1]6.8 (6.8–6.8) [1]0.8 (0.75–0.82) [3]6.2 (6.0–6.3) [3]
Prothrombin time, s9 (9–9) [2]28 (25–37) [5]
Chloride, mmol/L80 (75–85) [6]120.5 (115–126) [6]
Lithium, mmol/L1.5 (1.4–2.0) [3]
Uric acid, mg/dL1.0 (1.0–1.0) [1]12.9 (11.8–13.0) [4]
Phenytoin, μg/mL25 (25–30) [3]
Theophylline, μg/mL23 (23–25) [3]
Lactate, mg/dL0.5 (0.5–0.5) [1]31 (4.0–45) [3]
Amylase, U/L388 (350–470) [3]
ALT, U/L750 (500–1000) [2]
  • a n = No. of papers used as source of data.

  • b APTT, activated partial thromboplastin time; ALT, alanine aminotransferase.