At a Glance

Why It's Ordered
Is this infection causing organ dysfunction (sepsis), has it progressed to septic shock, and is the antibiotic and fluid pathway running on time?
Check First
Lactate, blood pressure after fluid, creatinine against baseline and platelets: the values that decide whether a patient is in septic shock and how fast treatment escalates.
Critical Values
Lactate ≥4 mmol/L · Platelets <20 or >1000 ×10³/µL · WBC <2.0 or >30 ×10³/µL · INR >5.0 · Glucose <40 or >450 mg/dL
Don't Miss
A normal qSOFA or normal blood pressure does not rule out sepsis. Lactate above 2 mmol/L means hypoperfusion until shown otherwise: start the sepsis pathway and repeat the lactate.
Field & Transport
Handheld lactate meter where stocked. Prenotify the sepsis screen, the source and the time of the first antibiotic; send the fluid volume in mL/kg, vasopressor rate and every repeat lactate.

Panel Overview

The Sepsis Workup Panel is the laboratory set that accompanies the sepsis bundle. It has 9 measured core components: lactate, creatinine, total bilirubin, platelet count, WBC, PT/INR, aPTT, glucose and total CO₂. Anion gap is a calculated value, and procalcitonin, C-reactive protein, blood cultures and urinalysis are add-on tests that find or support a source. It is drawn in the ED or on arrival at an ICU for suspected infection with organ dysfunction, and before transfer. It overlaps the CMP (glucose, total CO₂, creatinine, bilirubin) and the CBC and coagulation panels, which hold the full analyte sets.

When to Order:
  • Sepsis: suspected infection with hypotension, altered mentation, fast breathing or mottled skin
  • Septic shock: vasopressor need, or lactate above 2 mmol/L after fluid
  • Organ dysfunction: rising creatinine, falling platelets, bilirubin rise or prolonged INR
  • Source search: urinalysis, cultures and inflammatory markers when a source is unclear
  • Pre-transfer: any suspected sepsis that is leaving a facility, with a repeat lactate due en route

Perfusion & Organ Markers

Lactate

Normal: 0.5–2.2 mmol/L

Marks hypoperfusion and cellular stress. Above 2 mmol/L with a vasopressor need defines septic shock; high values also come from shock, seizure and drug or toxin effects.

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Creatinine

Normal: M 0.7–1.3 | F 0.6–1.1 mg/dL

Kidney marker and SOFA organ component. Interpret against baseline: a rise is AKI, and creatinine lags injury by 24 to 72 hours.

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Total Bilirubin

Normal: 0.1–1.2 mg/dL

Liver and SOFA organ component. Rises with cholestasis, hemolysis and hepatic hypoperfusion in septic shock.

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Platelet Count

Normal: 150–400 ×10³/µL

Falls with consumption in sepsis and DIC. Also a SOFA organ component; a falling count with a rising INR is a bleeding-risk signal.

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Blood Counts

White Blood Cell Count (WBC)

Normal: 4.5–11.0 ×10³/µL

Can rise or fall in sepsis. Read with the differential and trend; a low count in infection is a poor-prognosis marker, not a reassurance.

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Coagulation

PT/INR

Normal: INR 0.8–1.1

Prolongs with liver dysfunction, DIC and warfarin. Read with platelets and fibrinogen when bleeding or DIC is suspected.

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Activated Partial Thromboplastin Time (aPTT)

Normal: 25–35 s

Prolongs with DIC, heparin and factor deficits. Lab-calibrated; repeat when heparin is started or changed.

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Chemistry & Acid-Base

Glucose

Normal: 70–99 mg/dL (fasting)

Hyperglycemia is common in sepsis; hypoglycemia is a danger with insulin. Check it at the bedside whenever mentation changes.

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Total CO₂ (HCO₃⁻)

Normal: 22–29 mEq/L

Falls in lactic acidosis; the anion gap separates the causes of the acidosis.

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Calculated Values

Anion Gap

Normal: 4–12 mEq/L

Calculated from sodium, chloride and bicarbonate. Low albumin hides a raised gap, so correct it; a raised gap with lactate above 2 mmol/L fits lactic acidosis.

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Common Add-Ons

Urinalysis

Normal: negative nitrite and leukocyte esterase

Finds a urinary source. Pyuria, nitrite and casts point to infection or kidney injury; check it when the source is unclear.

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Procalcitonin

Normal: assay-specific

Does not decide whether to start antibiotics: SSC 2026 suggests clinical evaluation alone for that. It can help decide when to stop antibiotics (conditional).

C-Reactive Protein (CRP)

Normal: assay-specific

Nonspecific inflammatory marker. Trend it, do not use it to exclude or confirm sepsis at the bedside.

Blood Cultures

Normal: no growth

Identifies the organism. Collect them before the first antibiotic dose only when this does not delay it.

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Reference Ranges & Critical Values
TestAdult Normal (conventional)SI UnitsCritical LowCritical HighNotes
Lactate
0.5–2.2 mmol/L (4.5–20 mg/dL)
0.5–2.2 mmol/L
—
≥4 mmol/L
Sepsis flag above 2 mmol/L (above 18 mg/dL); repeat when raised
Creatinine
M 0.7–1.3 | F 0.6–1.1 mg/dL
M 62–115 | F 53–97 µmol/L
—
—
Sex-specific; compare with baseline
Total bilirubin
0.1–1.2 mg/dL
1.7–20.5 µmol/L
—
—
Trend with ALT, ALP and INR
Platelets
150–400 ×10³/µL
150–400 ×10⁹/L
<20
>1000
Lab-specific; falls in DIC
WBC
4.5–11.0 ×10³/µL
4.5–11.0 ×10⁹/L
<2.0
>30
Read with the differential
PT/INR
INR 0.8–1.1
INR 0.8–1.1
—
>5.0
Warfarin target differs by indication
aPTT
25–35 s
25–35 s
—
>100 s
Lab-calibrated; heparin-specific range
Glucose
70–99 mg/dL (fasting)
3.9–5.5 mmol/L
<40
>450
Random values differ; check on any mental-status change
Total CO₂ (HCO₃⁻)
22–29 mEq/L
22–29 mmol/L
<10
>40
Low in lactic acidosis
Anion gap
4–12 mEq/L
4–12 mmol/L
—
—
Analyzer-dependent; calculated
Note: Every lab sets its own intervals and critical values, and both shift with the analyzer and the assay. Use your laboratory's reported interval and its critical-call policy.

Systematic Interpretation
  1. Confirm organ dysfunction: Sepsis is suspected infection with an acute rise of 2 or more points in SOFA score (Sepsis-3). Read the SOFA components (platelets, bilirubin, creatinine and the other organ systems) against baseline. qSOFA is a prognostic score, not a screen.
  2. Perfusion and lactate: Lactate above 2 mmol/L (above 18 mg/dL) is the Sepsis-3 threshold. Septic shock means a vasopressor is needed for a mean arterial pressure of 65 mm Hg or higher, and lactate is above 2 mmol/L in the absence of hypovolemia.
  3. Organ markers: Check creatinine against baseline, bilirubin and platelets. These are SOFA components, and they set how severe the organ failure is.
  4. Counts: Read the WBC with the differential. Leukocytosis and leukopenia both occur in sepsis. Read the count against the trend and the clinical picture.
  5. Coagulation: Read PT/INR and aPTT alongside platelets. A prolonged INR and aPTT with falling platelets suggests consumptive coagulopathy. Check fibrinogen if the lab offers it.
  6. Acid-base and anion gap: Look at bicarbonate and the anion gap together. A raised gap with lactate above 2 mmol/L is lactic acidosis. Correct the gap for albumin before you call it normal. Hypoalbuminemia lowers the measured gap (about 2.5 mEq/L for each 1 g/dL that albumin is below 4 g/dL). A normal corrected gap with low bicarbonate points to another cause.
  7. Source: Order urinalysis, cultures and imaging as the clinical picture requires. Inflammatory markers support infection. They do not establish it.
Anion gap
Na⁺ − (Cl⁻ + HCO₃⁻)

The normal range is 4–12 mEq/L, and it depends on the analyzer. Albumin-corrected gap = measured gap + 2.5 × (4 − albumin in g/dL). Raised gap plus lactate above 2 mmol/L points to lactic acidosis.

Worked Example: Picture a 68-year-old with fever. BP 84/50 mm Hg (MAP about 61 mm Hg), lactate 3.1 mmol/L, WBC 18.0 ×10³/µL, platelets 110 ×10³/µL and creatinine 1.8 mg/dL against a baseline of 0.9 mg/dL. Organ dysfunction is already here, so sepsis is established. Still need a vasopressor to hold MAP at 65 mm Hg or higher after fluid, with lactate still above 2 mmol/L? That meets the Sepsis-3 definition of septic shock.

Patterns & Differential

Every pattern pairs the panel findings with the next step. Organ dysfunction on a suspected infection confirms sepsis. The patterns below pull it apart from its mimics.

PatternKey FindingsCommon CausesNext Step
Sepsis without shock
Organ dysfunction (creatinine, platelets, bilirubin or GCS change); MAP 65 mm Hg or higher without a vasopressor
Pneumonia, urinary, abdominal or skin source
Antibiotics and source control per pathway; fluid as needed; repeat lactate
Septic shock
Vasopressor needed for MAP 65 mm Hg or higher; lactate above 2 mmol/L after fluid
Same sources, with hypoperfusion
Vasopressor and antibiotic now; serial lactate; ICU
Sepsis with normal BP and high lactate
Lactate above 2 mmol/L with MAP above 65 mm Hg and no vasopressor
Early sepsis; mild hypoperfusion
Sepsis, not septic shock; repeat lactate and reassess
Consumptive coagulopathy
Platelets falling, INR and aPTT prolonged, fibrinogen low
Sepsis with DIC, trauma, obstetric and liver causes
Repeat coagulation tests; treat the cause; bleeding precautions
Lactic acidosis without infection
High lactate and gap; no organ-system infection signs
Cardiogenic shock, hemorrhage, PE, toxic ingestion, seizure
Treat the cause; see the E3 sepsis condition mimics
Urinary source
Pyuria, positive nitrite or leukocyte esterase; creatinine rise
Pyelonephritis, catheter infection, obstruction
Urinalysis and culture; bladder scan if urine output is low
Leukopenic infection
WBC below 4.5 ×10³/µL with fever or hypotension
Immunosuppression, overwhelming sepsis
Treat as sepsis regardless of count; do not treat the count as reassurance

Serial Testing & Kinetics
AnalyteRises or DetectablePeaksRepeat IntervalMonitoring Target
Lactate
Within hours of hypoperfusion
Varies with the cause
Serial measurements to guide resuscitation (SSC 2026, conditional); the interval is protocol-dependent, commonly 2 to 4 hours when the first value is above 2 mmol/L
Falling lactate with improving perfusion
Creatinine
Lags injury by about 24–72 hours
Varies; use the trend
Per clinical course and protocol
Return toward baseline; urine output
Platelets
Falls with consumption over hours to days
Varies
Per clinical course; daily while DIC is suspected
Stable or rising count
Total bilirubin
Rises over days
Varies
Per clinical course
Trend with INR and ALT
PT/INR and aPTT
Change with DIC or heparin
Varies
After heparin changes or bleeding; per protocol
Stable range for the indication

Trend beats one value. Lactate falling as blood pressure rises means perfusion is improving. Lactate that stays high despite adequate fluid is the signal to escalate.

Critical Findings & Emergency Actions

Suspected sepsis with hypotension or altered mentation (Paramedic/RN/CCT)

Recognize: Think sepsis when there is suspected infection with a MAP below 65 mm Hg, an SBP of 100 mm Hg or less with altered mentation, or mottled skin. Until proven otherwise, treat it as sepsis.

  1. Prenotify and secure access (Paramedic/RN/CCT): Call ahead with the screen result, the suspected source and the estimated arrival. Get IV or IO access per protocol.
  2. Cultures and lactate (Paramedic/RN/CCT): Draw blood cultures and a lactate only if they won't hold up the first antibiotic dose.
  3. Antibiotic (Paramedic/RN/CCT): Give the first dose per local protocol and medical direction. In septic shock, and in probable or definite sepsis without shock, give it right away, ideally within 1 hour of recognition (SSC 2026, strong). For possible sepsis without shock, run a time-limited rapid assessment. If concern for infection persists, get antimicrobials in within 3 hours of first suspicion (SSC 2026, conditional). Ask about beta-lactam allergy first. Agent choice depends on the source and the resistance risk. See the linked ceftriaxone and vancomycin pages.
  4. Crystalloid (Paramedic/RN/CCT): Run at least 30 mL/kg IV crystalloid over the first 3 hours for hypoperfusion (SSC 2026, conditional). Work the volume from actual body weight, or from adjusted or ideal body weight when BMI is over 30. SSC 2026 suggests balanced crystalloids over 0.9% saline (conditional). The exception is sepsis with traumatic brain injury, where 0.9% saline is suggested (conditional). Use a balanced crystalloid per protocol, such as lactated Ringer's. After each bolus, reassess lungs, oxygenation and blood pressure, and stop for overload. Don't keep running fluid until lactate normalizes. Individualize it after the first bolus, guided by the lactate fall (SSC 2026, conditional).

Septic shock: hypotension after fluid (Paramedic/RN/CCT)

Recognize: Still hypotensive after adequate fluid, needing a vasopressor to hold MAP at 65 mm Hg or higher, with lactate above 2 mmol/L? That is septic shock by the Sepsis-3 definition. In adults aged 65 or older, SSC 2026 suggests a MAP of 60 to 65 mm Hg (conditional).

  1. Vasopressor: Reach for norepinephrine per protocol, aiming at a mean arterial pressure of 65 mm Hg or higher (SSC 2026, strong). Norepinephrine is the first-line agent (SSC 2026, strong). High-alert Pump by mcg/kg/min or as the protocol states. Check concentration and rate at every bag change.
  2. Peripheral start: SSC 2026 suggests starting vasopressors peripherally to restore MAP, not waiting for central venous access (conditional). In unstable shock (severely reduced blood pressure, mottled skin, altered mentation), SSC 2026 notes that vasopressors may be started with fluid, case by case. Check the site at every reassessment. Manage extravasation per protocol and the norepinephrine page.
  3. Repeat lactate and reassess: Repeat the lactate, and reassess perfusion, mentation and urine output after each change. SSC 2026 suggests capillary refill time as an adjunct to other perfusion measures (conditional).

Escalating norepinephrine: add vasopressin (Paramedic/RN/CCT, protocol-dependent)

Recognize: The norepinephrine dose keeps climbing to hold MAP, and lactate stays above 2 mmol/L.

  1. Add vasopressin: SSC 2026 suggests adding vasopressin when norepinephrine doses escalate (conditional, with no fixed cut-off). High-alert Vasopressin label starting dose for septic shock is 0.01 units/min. Titrate it up by 0.005 units/min every 10 to 15 minutes to the target blood pressure. The label's septic-shock range is 0.01 to 0.07 units/min, and data above 0.07 units/min are limited. Many protocols use a fixed add-on of 0.03 units/min instead (see the linked vasopressin page). Follow local protocol for the pump.
  2. Keep titrating norepinephrine: Vasopressin does not replace norepinephrine titration to MAP.
  3. Watch for effects: Vasopressin can bring on bradycardia, ischemia (including digits and mesentery) and hyponatremia. Reversible diabetes insipidus can follow stopping it. Monitor rhythm, perfusion, sodium and urine output.

Persistent shock on vasopressors (ICU/CCT)

Recognize: The vasopressor need keeps going after fluid, and the dose keeps climbing.

  1. Corticosteroid: SSC 2026 suggests IV corticosteroids for septic shock (conditional). The sources checked for this page do not state criteria or dose. Follow the protocol and the linked hydrocortisone page.
  2. Escalate care: Get early ICU or specialist review. Reassess the source and cardiac function, which can coexist with septic shock.
  3. Invasive monitoring: arterial line and central access per protocol and ICU capability.

Lactate of 4 mmol/L or higher (RN/CCT)

Recognize: Most laboratories set the critical value at a lactate of 4 mmol/L or higher.

  1. Confirm the trend: Repeat the lactate per protocol, and check perfusion, mentation and blood pressure.
  2. Treat the cause: Start the sepsis pathway if infection is suspected. For other causes, use the mimics list in the Patterns table.
  3. Notify: Pass the critical result to the receiving team and in the handoff.
Pitfall: A high lactate with normal blood pressure is sepsis, not septic shock. Don't start a vasopressor for the lactate alone. If hypotension persists after fluid, start one per protocol. When hypotension is severe or life-threatening, a vasopressor may go in peripherally during fluid resuscitation, without waiting for the full volume (SSC 2026, case by case).

Prehospital & Transport Considerations

Point-of-Care Testing

Device / MethodAnalytesSpecimenLimitations
Handheld lactate meter
Lactate
Capillary or venous whole blood
Lab-specific accuracy; confirm high values with the lab; a meter is not a substitute for the sepsis screen
Glucometer
Glucose
Capillary blood
Unreliable in shock and dehydration; confirm low or high values with a lab
Blood gas analyzer (where stocked)
Lactate, pH, bicarbonate
Arterial or venous blood
Calibration, cartridge temperature and storage limits; analyze promptly

Interfacility Transfer & Handoff

  • Send with the patient: the first lactate and time, every repeat lactate and time, the last blood pressure and MAP, and mental status.
  • Antibiotics: agent, dose, route and time of the first dose; allergy status; cultures drawn and whether they were drawn before the antibiotic.
  • Fluids and vasoactives: total crystalloid in mL and mL/kg with times; vasopressor name, concentration, rate and start time; IV or IO site status.
  • Pending labs: cultures, repeat lactate, coagulation tests and any results not yet back, with who will follow them up.
  • En route: Repeat the lactate and reassess after each change if the protocol and transport time allow. Flight altitude and cold can change cartridge results, so follow device limits.

Scope Notes

  • Fluid volume, antibiotic choice and vasopressor titration follow local protocol and medical direction. This page does not state agency-specific scope.
  • Septic shock with an expected delay of more than 60 minutes to in-hospital evaluation? SSC 2026 suggests giving antibiotics in the ambulance or flight (conditional). That applies only once a structured prehospital sepsis screening process is in place. SSC 2026 also suggests a standard sepsis screening tool en route (conditional).
  • Use NEWS, MEWS or SIRS, not qSOFA, as the single screening tool for acutely ill patients in hospital. SSC 2026 recommends this (strong).

Special Populations

Pediatrics

The adult SSC 2026 guideline does not cover children. Adult thresholds and fluid volumes do not transfer to them. Use the current pediatric sepsis guideline (Surviving Sepsis Campaign International Guidelines for the Management of Sepsis and Septic Shock in Children 2026) and the local pediatric protocol. Every lab test has a pediatric reference interval, and it differs by age. For weight-based dosing and vital signs, use the linked pediatric pages: weight-based dosing and vital signs.

Pregnancy

Pregnancy shifts the normal ranges. In pregnancy, a creatinine above 0.8 mg/dL is abnormal, so a value that looks normal can hide early kidney injury. Sepsis in pregnancy runs the same antibiotic and fluid pathway, with early obstetric notification per protocol. Peripartum and postpartum infection is a common source. Ask about a recent delivery.

Older Adults

In older adults, a normal creatinine can hide reduced kidney function. Trend creatinine against baseline, and read urine output alongside it. For septic shock in adults aged 65 or older, SSC 2026 suggests a MAP target of 60 to 65 mm Hg (conditional). That target replaces 65 mm Hg or higher for this group.

CKD, Dialysis and Heart Failure

These patients have less room for fluid. Give smaller boluses, reassess lungs and oxygenation after each one, and stop for overload. Early vasopressor use may be needed in place of large fluid volumes.

Specimen Collection & Interfering Factors
  • Specimens: lactate (whole blood, analyzed promptly), CBC (lavender top), coagulation (light blue top), chemistry (gold or green top), urinalysis (clean catch) and blood cultures (bottles before the antibiotic dose when this does not delay it). Tube colours depend on the institution.
  • Handling: analyze lactate promptly; follow the laboratory's guidance on ice or time limits. Expel air bubbles from syringes.
  • Order of draw: Follow your laboratory's order-of-draw policy for blood cultures and tubes. In most policies, coagulation tubes come before the chemistry tube.
Error or InterferentEffect on ResultsPrevention
Delayed processing of lactate
Lactate can rise in a sample left at room temperature
Analyze promptly; send to the lab without delay
Hemolysis
Falsely raises potassium and some enzymes; not a main issue on this panel
Avoid forceful draws; reject hemolyzed samples per lab policy
Heparin contamination
Can alter coagulation tests and blood gases
Draw coagulation tubes without heparin carryover
Drawing above an IV line
Dilution that lowers glucose and other analytes
Draw from the opposite arm or stop the infusion per protocol
Warfarin or anticoagulant therapy
Prolongs INR and aPTT
Record drug and dose on the requisition
Hemodilution from large-volume fluid
Lowers platelets, Hgb and albumin on repeat draws
Interpret trends against the fluid given

Clinical Pearls
Field: Hypotension with fever or altered mentation is sepsis until proven otherwise. Start the screen and prenotify before the lab returns.
Field: Think of a handheld lactate as a trend tool. Repeat it when the protocol says, and write down the time of each result.
Nursing: Record MAP, urine output and mental status at each reassessment. Urine output often falls before the creatinine rises.
Critical care: Vasopressin is an add-on to norepinephrine. It is not a substitute for titrating norepinephrine to MAP.
Critical care: Septic shock takes both a vasopressor need and lactate above 2 mmol/L after fluid (Sepsis-3). Lactate alone does not define it.
Trend: Creatinine is a lagging marker. A normal value early in sepsis does not rule out kidney injury.
Bundle: The antibiotic clock starts at recognition, not at the lab result. Cultures and labs should not delay the first dose.
Pitfall: Don't use qSOFA alone to exclude sepsis. A negative qSOFA still needs the full screen (SSC 2026 strong recommendation).
Pitfall: The vasopressin label starts septic shock at 0.01 units/min. Many protocols use a fixed 0.03 units/min add-on instead (see the linked vasopressin page). Match the pump library to the protocol.

Related

References
  1. Singer M, Deutschman CS, Seymour CW, et al. The Third International Consensus Definitions for Sepsis and Septic Shock (Sepsis-3). JAMA. 2016;315(8):801–810. https://doi.org/10.1001/jama.2016.0287
  2. Prescott HC, Antonelli M, Alhazzani W, et al. Surviving Sepsis Campaign: International Guidelines for Management of Sepsis and Septic Shock 2026. Crit Care Med. 2026;54(4):725–812. https://doi.org/10.1097/CCM.0000000000007075
  3. Society of Critical Care Medicine. Surviving Sepsis Campaign International Guidelines for Management of Sepsis and Septic Shock 2026: adult guideline recommendations and grades. Accessed 2026. https://www.sccm.org/clinical-resources/guidelines/guidelines/surviving-sepsis-campaign-international-guidelines-for-management-of-sepsis-and-septic-shock-2026
  4. Evans L, Rhodes A, et al. Surviving Sepsis Campaign: International Guidelines for Management of Sepsis and Septic Shock 2021. Crit Care Med. 2021. Superseded by the 2026 guideline; cited for comparison of antibiotic timing. https://doi.org/10.1097/CCM.0000000000005337
  5. Par Health USA. Vasostrict (vasopressin) injection, prescribing information. DailyMed; label updated April 21, 2026. https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=b1147beb-743e-4c62-8927-91192447f8b8
  6. Weiss SL, Peters MJ, Oczkowski SJW, et al. Surviving Sepsis Campaign International Guidelines for the Management of Sepsis and Septic Shock in Children 2026. Pediatr Crit Care Med. 2026;27(4):379–434. https://doi.org/10.1097/PCC.0000000000003927

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