Blood Testing for Suspected Mild Toxicity After Flood Exposure in Nursing Home
For nursing home residents with suspected mild toxicity after flood exposure, obtain basic metabolic panel with electrolytes and anion gap calculation, complete blood count, liver function tests, and carboxyhemoglobin level if carbon monoxide exposure is possible from generators or heating equipment used during the flood. 1
Core Laboratory Assessment
Initial blood work should focus on detecting metabolic derangements and organ dysfunction that may result from chemical contamination in flood waters:
Obtain serum electrolytes, bicarbonate, and calculate the anion gap, as an elevated anion gap (>27 mmol/L) can indicate toxic alcohol ingestion, salicylates, or other metabolic poisons that may have been released from storage areas during flooding 1
Perform venous blood gas analysis to assess pH and metabolic acidosis, which helps identify toxic exposures and guide management 1
Order liver function tests (AST, ALT, bilirubin, albumin) as chemical contamination from industrial or agricultural chemicals mobilized during floods can cause hepatotoxicity 2, 3
Obtain complete blood count to assess for infection risk from sewage contamination and baseline hematologic status 3, 4
Check renal function (creatinine, BUN) as chemical exposures and dehydration during flood events can cause acute kidney injury 2
Carbon Monoxide Testing (Critical in Flood Settings)
Carbon monoxide poisoning is a significant risk in flood-affected facilities due to generator use and heating equipment:
Obtain carboxyhemoglobin level by co-oximetry on venous blood in all residents with altered mental status, headache, or exposure to generators or heating equipment during the flood 1, 5
Do not rely on pulse oximetry, as standard pulse oximetry cannot differentiate between oxyhemoglobin and carboxyhemoglobin, showing falsely normal readings even with COHb levels as high as 25% 5
Noninvasive pulse CO-oximetry has poor sensitivity (48%) and should not be used for diagnosis; laboratory-based spectrophotometry is required 2, 1
Context-Specific Considerations for Flood Exposure
Flood waters commonly contain multiple contaminants that require targeted assessment:
Chemical spills from industrial or agricultural areas adjoining residential facilities increase hazards, particularly pesticides and industrial chemicals that may be remobilized from the environment 3, 4
Heavy metals testing (lead, mercury, arsenic) may be warranted if industrial contamination is suspected based on the facility's geographic location and surrounding land use 2, 6
Consider testing for specific chemicals if the facility's location near factories or storage areas suggests particular exposures (e.g., volatile organic compounds, petroleum products) 3, 4
Electrocardiography
- Obtain 12-lead ECG in residents with chest pain, altered mental status, or suspected cardiotoxic exposures, as ECG findings may reveal QRS widening, QT prolongation, or dysrhythmias requiring specific management 1
Common Pitfalls to Avoid
Do not delay supportive care while awaiting laboratory results if clinical suspicion is high; initiate oxygen therapy and supportive measures immediately 1, 5
Do not assume normal pulse oximetry rules out carbon monoxide poisoning in residents exposed to generators or heating equipment; always obtain laboratory COHb measurement 5
Do not overlook cardiac complications, which can occur even with relatively low COHb levels or mild chemical exposures 5
Recognize that clinical severity may not correlate with measured toxin levels, and residents may have significant toxicity despite relatively low concentrations 5
Be aware that epidemiological evidence linking flood-related chemical contamination to specific morbidity patterns is limited, so maintain high clinical suspicion even when specific exposures cannot be confirmed 3