Glucose POC ACHS: Point-of-Care Testing Before Meals and at Bedtime
"ACHS" is medical shorthand for "ante cibum" (before meals) and "hora somni" (at bedtime), referring to the timing of point-of-care glucose monitoring that should be performed before breakfast, lunch, dinner, and at bedtime in hospitalized patients with diabetes who are eating.
Definition and Clinical Context
Point-of-care (POC) glucose testing is the standard of care for hospital glucose monitoring, using FDA-approved prescription glucose meters with capillary blood from finger sticks 1. The ACHS protocol specifically means:
- Before each meal (breakfast, lunch, dinner)
- At bedtime (hora somni)
This represents the minimum monitoring frequency for hospitalized patients who are eating 1.
Evidence-Based Monitoring Protocols
For Patients Who Are Eating
- POC glucose monitoring should be performed before meals 1
- This ACHS timing allows for appropriate insulin dosing decisions before food intake 1
- The American Diabetes Association 2024 Standards recommend this as the standard approach for hospitalized individuals with diabetes who are eating 1
For Patients Who Are NPO (Not Eating)
- Glucose monitoring is advised every 4-6 hours instead of ACHS 1
- This prevents unnecessary testing at meal times when patients aren't eating 1
For Patients on Intravenous Insulin
- More frequent monitoring ranging from every 30 minutes to every 2 hours is required for safe use 1
- This is the mandatory standard for IV insulin safety 1
Technical Specifications and Limitations
Accuracy Considerations
POC blood glucose meters are not as accurate or precise as laboratory glucose analyzers 1. Capillary blood glucose readings are subject to artifacts from:
- Perfusion abnormalities
- Edema
- Anemia or erythrocytosis
- Several medications commonly used in hospitals 1
Quality Standards
- Must use FDA-approved hospital-calibrated glucose monitoring systems 1
- Networked glucose meters that incorporate results into electronic health records represent a substantial advancement 1
- Any glucose result that doesn't correlate with clinical status should be confirmed by laboratory serum measurement 1
Clinical Targets for Hospital Glucose Management
Non-Critical Care Settings
The expert consensus recommends a target range of 100-180 mg/dL (5.6-10.0 mmol/L) for noncritically ill patients 1. Key considerations:
- Fasting glucose levels <100 mg/dL predict hypoglycemia within the next 24 hours 1
- Levels >250 mg/dL may be acceptable in terminally ill patients with short life expectancy 1
Critical Care Settings
- Insulin should be initiated for persistent hyperglycemia ≥180 mg/dL (≥10.0 mmol/L) 1
- Once therapy is initiated, target 140-180 mg/dL (7.8-10.0 mmol/L) for most critically ill individuals 1
- More stringent goals of 110-140 mg/dL may be appropriate for selected patients (e.g., post-surgical) if achievable without significant hypoglycemia 1
Safety Mandates
Safety standards prohibit sharing lanceting devices, testing materials, and needles 1. This is a mandatory requirement for all hospital glucose monitoring 1.
Emerging Technologies vs. Standard POC
While continuous glucose monitoring (CGM) shows promise for detecting hypoglycemia more effectively than POC testing 1, 2, POC testing remains the standard of care for hospital glucose monitoring 1. CGM has not been approved by the FDA for inpatient use as a standalone device for insulin dosing decisions 1.
Common Pitfalls to Avoid
- Never use POC results alone when they don't match clinical presentation—always confirm with laboratory testing 1
- Don't continue ACHS monitoring in NPO patients—switch to every 4-6 hour monitoring 1
- Avoid relying on POC meters in patients with severe physiological disturbances (hypoxemia, vasoconstriction, severe dehydration) where accuracy is compromised 1
- Don't forget quality control—ensure ongoing assessment of POC technique and device performance 1