Urgent Chemical Pathology results

The Chemical Pathology department will make every effort to inform clinicians of critical blood results which require urgent clinical intervention (These critical blood result phoning limits have been set in accordance with Royal College of Pathology guidelines and following consultation with CCG clinical lead and secondary care clinicians).

The stated limits serve as a guide only (below;) they are not exhaustive and laboratory staff should check with the Chemical Pathology Consultant, if unsure as to the suitability of communicating given data-sets by phone.

Generally, if the observed data is consistent with past (deranged) findings that have already been communicated as a matter of urgency previously, then the most recent results will not typically be phoned but will instead be released in the normal manner unless specifically requested otherwise.

Critical result limits

 

Analyte

In-patients

GP/ Out-patients

Comments

ALT (U/L)

≥600 (15x ULN)

As for in-patients

 

Ammonia (umol/L)

100

N/A

 

Amylase (U/L)

≥250

As for in-patients

 

AST (U/L)

≥675(15x ULN)

As for in-patients

 

 

 

 

 

Bilirubin – Direct/Conj (µmol/L)

≥25 Neonates

As for in-patients

 

Calcium corrected (mmol/L)

≤1.8    ≥3.5

As for in-patients

Primary Care: If out of hours (OOHs) then communication

next day to GP or GP OOHs service. Calcium levels ≥ 3.5

mmol/L may warrant more immediate communication with

Primary Care as agreed by local consensus.

CK   (U/L)

≥5000

As for in-patients

Changed in line with RCPath guidelines, previous cut off was 2000 U/L

Cortisol (nmol/L)

≤50.0

 

≤250

As for in-patients

Telephoning not required if post-dexamethasone suppression test

As part of short synacthen test. Cut point used may need to

be specific to assay being used

Creatinine (µmol/L)

≥354

(≥ 200 if < 16 yrs)

≥354

(≥ 200 if < 16 yrs)

Agree, by local consensus, higher thresholds for phoning

results in patients with known kidney disease including

those on dialysis. Specific local cut points likely to be

required for babies and neonates.

CRP (mg/L)

 

≥300

Primary care/GP’s  only

CSF Xanthochromia

Phone all results

N/A

Refer to LP-BIO-P716 for sample collection details

Digoxin (nmol/L)

≥3.0

As for in-patients

Check that timing is > 6 hrs since last dose.

 Phone if >2.0 if [K+] or [Mg2+] low and/or in renal impairment

Ethanol (mg/dl)

≥400

N/A

 

Glucose (mmol/L)

≤2.5  ≥25.0 (≥15 mmol/L if <16 y

 

≥25.0 if no previous record, new diabetic

 

30mmol/L in known type 2 DM

Exact cut points and response should be determined locally.

Glucose results < 2.5 mmol/L from primary care may be less

crucial to phone immediately. For GPs and OPD, upper cut

point of 30 mmol/L in known type 2 DM may be more

appropriate.

Iron (µmol/L) –Only applicable to high risk patients e.g bariatric surgery patients on long term high doses of iron supplements, pregnant patient

≥50 Adults

As for in-patients – contact on-call consultant in first instance

 

Lithium (mmol/L)

≥1.5

As for in-patients

 

Magnesium (mmol/L)

≤0.4

As for in-patients

 

Paracetamol (mg/L)

≥25.0

As for in-patients

Note time of ingestion if given

Phenytoin (µmol/L)

≥80 if [Alb] >40g/L

≥60 if [Alb] <35g/L

As for in-patients

 

Phosphate (mmol/L)

≤0.3

As for in-patients

 

Potassium (mmol/L)

≤2.5   ≥6.5

As for in-patients*

 

Exclude haemolysis/old samples/EDTA contamination first.

Agree, by local consensus, higher thresholds for phoning

results in patients with known kidney disease including

those on dialysis.(Please suggest if you agree to a higher phoning limit for this category of patients)

Salicylate (mg/L)

≥300.0

As for in-patients

Note time of ingestion

Sodium (mmol/L)

≤120 ≥160

<120 >160

≤130 mmol/L or >150 if <16y

Theophylline (µmol/L)

≥130 Adults

≥65 Children

As for in-patients

 

 

 

 

 

 

Troponin I (ng/L)

N/A

≥16 – Female

≥34 – Male

 

Urate (mmol/L)

 

≥0.34

Ante –natal patients only

Urea (mmol/L)

30 (≥ 10 if< 16 yrs)

Same as inpatients

Agree, by local consensus, higher thresholds for phoning

results in patients with known kidney disease including

those on dialysis. Specific local cut points likely to be

required for babies and neonates

For all out of hours clinical virology advice, please contact the infectious diseases registrar at BartsHealth (via Royal London switchboard. Short dialling code 6004)

 

 *(<2.8 >6.5 if OOH - all out of range results (2.5-6.5) to be phoned to GP next working day regardless)