Laboratory Updates

Monday 16 September 2019

As part of our ongoing efforts to maintain the highest quality standards in laboratory medicine, WestPac Labs would like to inform you of the following improvements:

In collaboration with the National Kidney Foundation (NKF), a new “Kidney Profile” will be offered to simplify the ordering and reporting of essential tests for assessment of chronic kidney disease. Specifically, the “Kidney Profile” provides an estimated glomerular filtration rate (eGFR) and a urine albumin to creatinine ratio (ACR). eGFR and ACR are the primary components of NKF algorithms for screening and staging of chronic kidney disease. The eGFR and ACR require paired serum and random urine specimens. To learn more please visit: https://www.kidney.org/CKDintercept/laboratoryengagement.
In accordance with National Kidney Foundation Guidelines, eGFR calculations will no longer be reported for patients less than 18 years of age.
As a result of Sonic Healthcare USA population studies and feedback from our clients, our reference range for peripheral blood white blood cell count (WBC) will be adjusted to 3.5 – 10.0 k/ul (previously 4.5 – 11.0).
Hemoglobin A1c results will be accompanied by the calculated estimated average glucose concentration (eAG) as recommended by the American Diabetes Association and American Association of Clinical Chemistry. The previously reported mean blood glucose (MBG) calculation for will be discontinued. eAG calculations average 8.4% lower than MBG over a range of A1c values from 5.0-8.0%.
Serum free testosterone in the “Testosterone Profile” will default to a calculated free testosterone. The Testosterone Free Direct by Enzyme Immunoassay (EIA), TC: 904 will no longer be available. Calculated free testosterone levels correlate well with reference methods and are satisfactory for most clinical situations. When a direct free testosterone measurement is clinically required (females and prepubertal males), this test should be individually ordered and will be sent to our reference laboratory for analysis by liquid chromatography-tandem mass spectrometry (LC-MS/MS), which is the gold standard method. In the event an order is received requesting the Testosterone Free Direct by EIA, a call will be placed to the provider and alternative testing options will be offered.

In order to better align with national clinical chemistry standards, the following changes will occur:

We will discontinue calculated estimates of ionized (free) serum calcium. Importantly, direct measurement of ionized serum calcium, which is the national laboratory standard, will continue to be offered.
Serum osmolality calculations will be discontinued as part of the basic and comprehensive metabolic profiles, as well as the renal function profile. Direct serum osmolality measurement should be ordered if needed for acid/base, electrolyte or pituitary disorder workups.
Plasma ammonia unit of measure will be standardized to micromole/liter (umol/l). The previous unit of measure for ammonia was microgram/deciliter (ug/dl).
Pediatric reference ranges for thyroid stimulation hormone (TSH) have been adjusted to more closely reflect biologic age stratification.
Urine drug screen panels will discontinue testing for propoxyphene and methaqualone. The prevalence of these drugs appear nil in our patient population. Propoxyphene (Darvon, Darvocet) was withdrawn from the US market in 2010. Methaqualone (Qualude) was a common drug of abuse in the 1960s and 1970s but is now encountered very uncommonly in the US.
We are pleased to offer Helicobacter pylori detection via the urea breath test (preferred) or the stool antigen test as recommended by the American College of Gastroenterology and College of American Pathology. Per these consensus guidelines, H. pylori serology (IgM, IgG) will be discontinued.
Our Critical Value and Alert Value List has been updated to include an expanded microbiology section. All critical values are telephoned to clients within 60 minutes of test completion. Alert values are telephoned during business hours only. The Critical and Alert Value List is attached for your reference.

WestPac Labs greatly appreciates your business and support, as we continually improve our service. Please do not hesitate to call if we can be of any assistance to you.

Sincerely,

Ronald Rocha, MD
Laboratory Director, WestPac-Santa Fe Springs

Zoltan Nagymanyoki, M.D., Ph.D.
Laboratory Director, WestPac-Bakersfield

Brandie Firetag, MD
Laboratory Director, WestPac-Central Coast

Visit us online at www.westpaclab.com or call 877.527.5227 for more information.

Critical and Alert Values

Chemistry

Analyte	Units	Critical Limits	Alert Limits
Albumin (<18y)	g/dL		<1.7 or >6.8
ALT	U/L		>500
Amylase	U/L		>700
AST	U/L		>500
BUN	mg/dL		>80
Calcium	mg/dL	<6.6 or >13.0
Chloride	mg/dL		<80 or >120
CK-MB	ng/mL	F >4.31; M >7.71
CO2	mEq/L		<10 or >40
CPK	U/L		>600
Creatinine	mg/dL		>5.0
Glucose Fasting	mg/mL	<45 or >400
Glucose Random	mg/mL	<45 or >500	>400
Iron	ug/dL		>350
Magnesium	mg/dL		<1.2 or >5.0
p02	mmhg	<40
pCO2	mmhg	<20 or >70
pH	units	<7.20 or >7.60
Phosphorus	mg/dL		<1.0 or >9.0
Potassium	mEq/L	<3.0 or >6.1
Sodium	mEq/L	<120 or >155
Total bilirubin (<1m)	mg/dL		>18.0
Total protein	g/dL		<3.2 or >9.5
Troponin I	ng/mL	>0.2
Troponin T	ug/mL	>0.01
TSH (<18y)	mIU/L		>40
Uric Acid	mg/dL		>13.0

Hematology

Analyte	Units	Critical Limits	Alert Limit
Blast %	%	>10%
CSF Cell Count	pmns	>5
HCT (<1m)	%	<21.0 or >81.0	<24.0 or >75.0
HCT (>1m)	%	<21.0 or >63.0	<24.0 or >60.0
HGB (<1m)	g/dL	<7.0 or >27.0	<8.0 or >25.0
HGB (>1m)	g/dL	<7.0 or >21.0	<8.0 or >20.0
INR	ratio	>5.0
Platelets	k/uL	<10 or >1500	<50 or >850
PTT	seconds	>60.0
WBC (<1m)	k/uL	>40.0	<2.0
WBC (>1m)	k/uL	>40.0	<2.0

Microbiology

Analyte	Critical Limits	Alert Limit
Ascites Gram Stain or Culture		Positive
Blood Culture	Positive
C.Difficile		Positive
Clinically Significant Fungi: Zygomycetes, Coccidiodes, Histoplasma, Blastomyces, Cryptococcus, Pneumocystis		Positive
CLostridium in Wounds		Positive
CRE: E.Coli, K.pneumoniae, K.oxytoca		Positive
CSF Gram Stain or Culture	Positive
ESBL: E.Coli, K.pneumoniae, K.oxytoca		Positive
MRSA		Positive
Multi-Drug Resistant: Pseudomonas aeruginosa, Acinetobacter spp.		Positive
Mycobacterium species (any type)		Positive
Neiseria gonorrhoeae (GC) (any detection method)		Positive
Ocular and Bone Marrow Cultures or Gram stain		Positive
Pleural Fluid Culture or Gram Stain		Positive
Rapid Influenza A/B assays		Positive
RSV		Positive
Stool Culture		Positive
Synovial Fluid Culture or Gram stain		Positive
Vancomycin Resistant: Enterococcus faecalis, Enterococcus faecium (excluding Resp Sources: Sputum, Nasal, Throat)		Positive

Toxicology/TDM

Analyte	Units	Alert Limit
Carbamazepine (Tegretol)	ug/mL	>20.0
Digoxin	ng/mL	>2.5
Lithium	meq/L	>1.5
Phenobarbital	ug/mL	>60.0
Phenytoin	ug/mL	>20
Theophylline	ug/mL	>20
Valproic Acid	ugm/mL	>200
Vancomycin	ugm/mL	Trough >20; Peak >44.0

Measles IgG Assay

WestPac Labs has partnered with our instrument manufacturer, DiaSorin, to adjust the cut-off zones for our Measles IgG assay which uses the chemiluminescent immunoassay method. The intent is to better-align with World Health Organization (WHO) international standards. The new reference range reflects a downward shift, and is as follows:

Measles IgG Reference Range Update

Old Reference Range	NEW Reference Range
Negative/Non-Immune ......< 25 AU/mL	Negative/Non-Immune ...< 13.5 AU/mL
Equivocal .........................25-30 AU/mL	Equivocal ...................13.5-16.5 AU/mL
Positive ..............................> 30 AU/mL	Positive ...........................> 16.5 AU/mL

It is expected that laboratories tracking their populations will see increased positivity and decreased negativity with the implementation of these new cut-offs. If you have any questions, please feel free to reach out to us.

R. Rocha, MD

Laboratory Director, Westpac Labs-Santa Fe Springs