Sources: "Review of Laboratory Values" inservice (Benson, Jan 2025, based on the 2023 APTA resources); APTA Academy of Acute Care PT Laboratory Values Interpretation Resource (2017); Allen OT Orientation Packet hold criteria (2021).
📌 Three principles before any number
🚨 Hold therapy and check with the first-contact provider when:
| Lab | Reference | Hold therapy? | Notes |
|---|---|---|---|
| Hemoglobin | M 14–17.4 · F 12–16 g/dL | <7, or a significant one-day drop → check with first contact. <8 = no OOB (dept rule). | Watch fatigue, dyspnea, dizziness. Pace anemic patients; use RPE. 1 unit PRBC ≈ Hgb +1 / Hct +3. Fluid boluses dilute H&H (hemodilution); dehydration falsely elevates the CBC (hemoconcentration). |
| Hematocrit | M 42–52% · F 37–47% | <24 = dept hold; APTA: <25% symptom-based with team input. | Expect impaired endurance; progress slowly; monitor SpO2, tachycardia, orthostasis. |
| WBC | 5–10 ×10⁹/L | Maybe — symptom-based (fever, malaise, exercise intolerance). | Fever may bring tachycardia — consider underlying heart disease. If neutropenic (<1.5; severe <0.5), ask first contact whether the patient may leave the room; take precautions. |
| Platelets | 140–400 k/uL | High: no. Low: discuss with first contact — critical <50k; significant bleeding risk ≤20k; likely hold <10k. | Fall prevention is the priority (spontaneous hemorrhage risk). Hold percussion/vibration chest PT and NTS for platelets <30k (dept practice). Evidence gives no absolute cutoff — collaborate. |
| Lab | Reference | Hold therapy? | Notes |
|---|---|---|---|
| Sodium | 134–142 mEq/L | Depends on mental status. | High or low → confusion, lethargy, seizure risk. Low Na: cerebral edema risk; corrected slowly (osmotic demyelination). Monitor orthostasis. Seizure precautions if history. |
| Potassium | 3.7–5.1 mEq/L | Defer until corrected if heart disease / arrhythmia history, or any EKG changes. Otherwise confer with first contact; go by vitals/symptoms. | Arrhythmias, weakness, paresthesias, cramps. Teams correct K+ fast — check when the value resulted. Consider lowering treatment intensity. Hemolyzed samples read falsely high. |
| Glucose | 70–100 mg/dL (inpatient target 140–180; critically ill 110–140) | Hold <70, or <100 with symptoms. Reach out to the team for <100 or >250; dept hold >300. | Low: shakiness, sweating, confusion, perioral/hand tingling. High: fatigue, thirst, polyuria. A1c ≥6.5% = diabetes; diabetic goal <7%. |
| Calcium | 8.6–10.3 mg/dL | Generally no. | Monitor rhythm and vitals; watch confusion, weakness, paresthesias; seizure precautions if low. |
| Magnesium | 1.2–1.9 mEq/L | No — but with heart disease / arrhythmia history, best corrected before PT. | Arrhythmias, cramps, tremors/spasticity when low. |
| Chloride | 98–108 mEq/L | Rarely — depends on cognitive status. | — |
| CO2 | 20–30 mmol/L | Metabolic acidosis (low CO2) may warrant a hold depending on severity — consult the team. | Monitor vitals, rhythm, and breathing pattern; use RPE/dyspnea scales. |
| BUN / Creatinine | BUN 6–25 mg/dL · Cr M 0.7–1.3, F 0.4–1.1 mg/dL | No — proceed on symptoms. | Renal function markers. Expect fatigue and reduced tolerance; auscultate lungs, check edema and cognition; renal dysfunction drives electrolyte abnormalities. |
| Lab | Hold therapy? | Notes |
|---|---|---|
| High-sensitivity troponin | STRONG HOLD: initial elevated value, up-trending values, or awaiting the repeat draw. Start therapy once stable or down-trending; discuss stable-but-elevated with the team. | Watch for unstable cardiac indicators: pending diagnostics, arrhythmias, unstable vitals, inotropes/pressors. Stop therapy for: RR >40, HR drop >10 bpm, SBP drop >10 mmHg, or SpO2 <90% with activity. |
| NT-proBNP | No — proceed with caution. | Heart-failure marker: watch for S3, chest pain, dyspnea, rhythm change, worsening crackles, hypotension. Use RPE. |
| Creatine kinase | No — but keep therapy functional. | Avoid overexertion/repetitive work in myositis; watch for compartment syndrome in rhabdomyolysis. |
| Lab | Reference / critical | Hold therapy? | Notes |
|---|---|---|---|
| INR | Therapeutic 1.5–3.5; possible critical >5 | >5.5 → discuss risk/benefit with first contact. Low values never contraindicate PT. | Monitors warfarin. Fall prevention; watch for bleeding/bruising and neuro changes. |
| aPTT | Therapeutic 51–83 s (1.5–2.5× control); possible critical >70 s | No — proceed with caution if elevated. | Monitors heparin. Same bleeding/fall precautions. |
| Anti-Factor Xa | — | No. | More reliable monitor of UFH/LMWH. Same precautions. |
For a new DVT or PE, mobilization timing depends on the anticoagulant and time since administration — follow the department algorithm (posted in the office; summarized from the APTA VTE CPG): roughly, wait a few hours after the first therapeutic dose of LMWH/UFH/NOAC and confirm therapeutic INR (2–3) for warfarin; check for an IVC filter when anticoagulation is contraindicated. See also the Post-Op Care hold list.
| Disorder | Pattern | Implication |
|---|---|---|
| Respiratory alkalosis | pH ≥7.45, PaCO2 ≤35 | Coordinate treatment around ventilation; expect somnolence and fatigue. |
| Respiratory acidosis | pH ≤7.35, PaCO2 ≥45 | |
| Metabolic alkalosis | pH ≥7.45, HCO3 ≥30 | |
| Metabolic acidosis | pH ≤7.35, HCO3 <24 | Coordinate mobility around dialysis; arrhythmia risk with mobility (esp. pH <7.1); may warrant hold — consult team. |
Normal: pH 7.35–7.45 · PaO2 80–95 · PaCO2 37–43 · HCO3 20–30.
⚠️ Spine-specific reminders Post-op spine patients commonly drop their H&H (surgical blood loss ± hemodilution) — check the trend before the first mobilization, screen for orthostasis, and remember the orthostatic hypotension management steps. Calf pain + anticoagulation questions → think DVT and check for pending dopplers before treating. No NSAIDs for spine patients regardless of labs (see Precautions).