Quick guide to get you started with Medical Biochemistry Assistant
Calc Tab: Browse and open clinical calculators. Enter values
and results appear instantly. Click unit badges to switch between units.
QC Tab: Upload and analyze quality control data with
Levey-Jennings charts, Westgard rules, and statistical summaries. Includes PBRTQC, RCV, Sigma
metric, and Carryover analysis tools.
Guide Tab: Reference guides, clinical ranges, and
interpretation notes for laboratory parameters. Fetch the latest articles from leading journals
via PubMed integration.
Notes Tab: Save personal notes and observations. Your data
stays in your browser's local storage.
Pro Tips: Hover over buttons for explanations. Use the
Clear All button to reset a calculator. Click Info & Guide
inside calculators for clinical context.
MEDICAL BIOCHEMISTRY ASSISTANT
Professional Laboratory Tool
Spot Urine Analysis
Used as a rapid screening tool to estimate daily protein excretion using the Protein/Creatinine
ratio when 24-hour collection is impractical. Highly correlated with total protein loss in
diabetic nephropathy screening and preeclampsia monitoring; however, results can be misled by
orthostatic proteinuria or exercise if the first morning void is not used.
mg/dL
mg/dL
U/L
mg/dL
mg/dL
mEq/L
µg/L
mg/dL
mEq/L
mg/dL
mEq/L
mg/dL
mg/dL
µg/dL
mg/dL
mg/L
mg/L
mg/L
mg/L
µg/L
µg/L
µg/L
µg/L
µg/L
µg/L
µg/L
mg/L
mg/L
mg/L
mg/L
mg/L
mg/L
Calculation Method (Spot Urine Ratios):
Analyte Ratio = (Spot Analyte ÷ Spot Creatinine) × Factor *Factors: 1000 for mg/g Cr, 100 for mEq/g, U/g, or µg/g
Cr.
Manual Dilution Planner
A laboratory optimization tool used to accurately calculate the required volumes for diluting
high-concentration samples that exceed the instrument's linearity range. This is not a
diagnostic test but a process tool to ensure result accuracy by minimizing manual pipetting or
calculation errors.
µL
Recipe adjusts to
ensure at least this amount of sample is used.
(If
not listed above)
(Enter
to see final result)
24-Hour Urine Calculation
The gold standard for the definitive assessment of proteinuria and renal function (creatinine
clearance) when nephrotic syndrome or kidney failure is suspected. It clarifies total daily loss
to guide treatment decisions like biopsy or drug dosing; however, patient compliance is critical
as collection errors directly invalidate the results.
mL
mg/dL
U/L
mg/dL
mg/dL
mEq/L
mEq/L
µg/L
mg/dL
mg/dL
mEq/L
mg/dL
mg/dL
mg/dL
mg/L
mg/L
mg/L
µg/L
mg/L
mg/L
mg/L
mg/L
µg/L
µg/L
µg/L
µg/L
µg/L
µg/L
µg/L
Calculation Method (24h Excretion):
Daily Excretion = Urine Concentration × Urine Volume × 0.01 (Factor for mg/dL to mg/day) *Results are normalized to total volume provided. Matched
units (e.g., mg/day, mEq/day) are displayed.
A fundamental parameter for staging chronic kidney disease and adjusting drug dosages by
estimating actual filtration rather than relying solely on creatinine. Highly sensitive for
early detection of renal decline, but may be unreliable in dynamic processes like acute kidney
injury where creatinine levels are not in steady-state.
Female
Male
Non-Black /
Other
Black
Year
kg
mg/dL
mg/L
Low-Density Lipoprotein (LDL) Calculator
Used in routine lipid panels to manage coronary artery disease risk and set statin therapy
goals. Calculated from total cholesterol, HDL, and triglycerides; however, the formula becomes
mathematically invalid if triglycerides exceed 400 mg/dL, requiring direct LDL measurement.
mg/dL
mg/dL
mg/dL
Homeostatic Model Assessment for Insulin
Resistance (HOMA-IR)
Quantitatively assesses insulin resistance at the tissue level, even before a diabetes diagnosis
is made. Valuable for early risk determination in metabolic syndrome or PCOS; however, the
calculation is invalid in patients using exogenous insulin or those with exhausted beta-cell
reserves.
mg/dL
µIU/mL
Schwartz Formula (Pediatric GFR)
Bedside Schwartz Equation (Revised 2009):
Used for children aged 1-16 years: eGFR = 0.413 × [Height (cm) / Serum Creatinine
(mg/dL)]
IDMS Requirement:
This formula applies to enzymatic serum creatinine measurements calibrated to reference
measurements by isotope dilution mass spectroscopy (IDMS), but not to alkaline picrate
("Jaffe") methods, even those traceable to IDMS. (For more information see National Kidney
Disease Education Program.)
Original Schwartz (Jaffe-based) Constants (k):
If using older Jaffe methods, the formula eGFR = k × [Height / Scr] applies with
specific constants:
Preterm infants: k = 0.33
Full-term infants (<1 year): k=0.45
Children and adolescent girls: k = 0.55
Adolescent boys: k = 0.70
Important Considerations:
- Enzymatic creatinine assays are preferred in children because non-creatinine chromogens
can cause significant errors at low creatinine values.
- The formula may overestimate GFR, especially in patients with low muscle mass or at lower
GFR levels.
- Accuracy significantly decreases when GFR > 103 mL/min/1.73m².
References:
Schwartz GJ, et al. New equations to estimate GFR in children with CKD. J Am Soc
Nephrol. 2009.
Schwartz GJ, et al. The use of plasma creatinine concentration for estimating
glomerular filtration rate in infants, children, and adolescents. Pediatr Clin North
Am. 1987.
Counselman FL, et al. Comparison of the glomerular filtration rate in children by
the new revised Schwartz formula and a new generalized formula. Kidney Int. 2013.
Bedside Schwartz Equation - Dr. Oracle Medical Advisory Board.
Original Schwartz
Revised Bedside Schwartz
Preterm (0.33)
Term Infant (0.45)
Child (0.55)
Adolescent Girl (0.55)
Adolescent Boy (0.70)
mg/dL
cm
Fibrosis-4 (FIB-4) Score
A non-invasive screening tool for advanced liver fibrosis risk in patients with fatty liver
disease (NAFLD). High reliability in excluding cirrhosis to prevent unnecessary biopsies; Note
that scores naturally increase with age, and the exclusion threshold may be higher in patients
over 65.
Year
10³/µL
U/L
U/L
D-Dimer Universal Converter
Standardizes D-Dimer results between potentially different laboratory units (FEU vs. DDU) to
prevent misinterpretation in VTE/PE exclusion. Mixing up units can lead to unnecessary
anticoagulation or missed diagnoses; unit confirmation is mandatory before clinical decisions.
Fibrinogen Equivalent Units (FEU)
D-Dimer Units (DDU)
1 DDU = 2 x FEU | Örn: 250 ng/mL DDU = 500 ng/mL FEU
Smart Dilution Planner
Used in medical laboratories to calculate stepwise dilution ratios needed for antibody titer
determination or analysis of highly concentrated samples. This is an analytical process tool,
not a diagnostic test; the accuracy of the prepared solutions directly impacts the reliability
of the final result.
Enter
the
starting concentration of your source solution.
(Optional)
The
system will
find the best path to reach this value.
µL
Volume
to be
pipetted from the previous tube in each step.
*If blank, 100 µL is used
automatically.
Corrected Sodium
Vital in evaluating severe hyperglycemia (DKA/HHS) to distinguish if low sodium is a true
deficiency or a dilutional (pseudohyponatremia) effect of glucose. This prevents inappropriate
saline replacement and associated risks of cerebral edema while predicting the sodium rise
during treatment.
mEq/L
mg/dL
Corrected Calcium
Identifies "pseudohypocalcemia" in patients with hypoalbuminemia (malnutrition, malignancy).
Even if total calcium appears low, physiologically active calcium may be normal. If blood pH is
abnormal, albumin binding changes and this formula loses reliability; in such cases, ionized
calcium measurement is the gold standard.
mg/dL
g/dL
Corrected Magnesium
Distinguishes whether low magnesium levels in hypoalbuminemic patients represent a true
deficiency or merely a decrease in the carrier protein. Critical for identifying real magnesium
deficits in cases of refractory hypocalcemia or hypokalemia, although its clinical validation is
less definitive than corrected calcium.
mg/dL
g/dL
Serum Anion Gap
In metabolic acidosis of unknown origin, this determines if the cause is acid addition (High AG
- e.g., ketoacidosis, lactate) or bicarbonate loss (Normal AG - e.g., diarrhea). In the presence
of hypoalbuminemia, the calculated value will be misleadingly low; therefore, a correction
factor must be added for every 1 g/dL drop in albumin.
mEq/L
mEq/L
mEq/L
g/dL
Serum Osmolality & Osmolal Gap
Checks for the presence of an "osmolal gap" by comparing calculated and measured osmolality.
This is critical for detecting alcohol (ethanol, methanol, ethylene glycol) poisoning. A normal
gap (<10) helps exclude toxic ingestion; note that if ethanol is not included in the formula,
the gap will appear artificially high in patients who have consumed alcohol.
mEq/L
mg/dL
mg/dL
mg/dL
mOsm/kg
Fractional Excretion of Sodium (FENa)
Differentiates between prerenal azotemia (<1%) and acute tubular necrosis (>2%) in oliguric
acute kidney injury by measuring the kidney's sodium-retaining ability. Result is
invalid in
patients using diuretics because sodium excretion is disrupted; in those cases,
Fractional
Excretion of Urea (FEUrea) should be used instead.
mEq/L
mg/dL
mEq/L
mg/dL
Serum-Ascites Albumin Gradient (SAAG)
In patients with ascites, this more clearly distinguishes between portal hypertension (e.g.,
cirrhosis, heart failure) and peritoneal involvement (e.g., cancer, tuberculosis) than
Light's
criteria. A difference >1.1 g/dL indicates portal hypertension; blood and fluid samples must
be
taken simultaneously for accurate results.
g/dL
g/dL
Pleural Fluid pH Estimation
Used to estimate the acidity of the environment via the Henderson-Hasselbalch equation when
blood
gas analyzers are unavailable or for pleural/ascitic fluid analysis. While it provides a
quick
idea, it is not as precise or reliable as a dedicated blood gas device for directing
treatment
in critical acidosis or alkalosis.
mmol/L
mmHg
Mentzer Index
A screening tool for microcytic anemia (low MCV) to distinguish between simple iron
deficiency
and genetic Thalassemia trait. An index >13 favors iron deficiency, while <13 favors
thalassemia; note that results are unreliable in patients who have both conditions
simultaneously.
fL
10⁶/µL
Albumin/Globulin Ratio
Used to understand the direction of unexplained total protein changes. A low ratio (<1)
helps distinguish between increased globulin production (Multiple Myeloma, chronic
infection, autoimmunity) and selective albumin loss (nephrotic syndrome). Should be
interpreted alongside the patient's hydration status, as dehydration can mask
changes.
g/dL
g/dL
Red Blood Cell (RBC) Indices
Derived from hemoglobin, hematocrit, and red cell count for the morphological
classification of
anemia (microcytic, normocytic, macrocytic). Fundamental for manual control or when
automated
counters are unavailable; however, the count and calculation will be distorted in
the presence
of cold agglutinins.
g/dL
%
10⁶/µL
Corrected Reticulocyte Count
Evaluates whether the bone marrow is responding appropriately to anemia
(regenerative vs. hypoproliferative). The raw reticulocyte percentage can look
misleadingly high due to a low hematocrit; this calculation provides the
"reticulocyte production index" to reveal the marrow's true performance.
%
%
%
International Normalized Ratio
(INR) Calculator
Standardizes prothrombin time (PT) results across different laboratories to manage
bleeding or clotting risks, especially for patients on warfarin. Essential for
dosage adjustment; note that INR can be elevated in liver failure even without
anticoagulants, which may not perfectly reflect bleeding risk.
sec
sec
-
Blood Urea Nitrogen
(BUN)/Creatinine Ratio
Differentiates between prerenal causes (dehydration, heart failure) and renal
parenchymal damage in acute kidney injury. A ratio >20 strongly supports prerenal
azotemia or increased protein load (e.g., GI bleed); however, steroid use and
catabolic states can also raise the ratio independently of renal function.
mg/dL
mg/dL
Arterial Blood Gas (ABG)
Validation [H+]
A laboratory quality control tool that tests the technical reliability of blood gas
results by checking the mathematical balance (Henderson-Hasselbalch) between pH,
pCO2, and HCO3. It helps detect instrument errors or improper sample handling before
clinical intervention.
mmHg
mmol/L
Free Androgen Index (FAI)
In women suspected of PCOS or hirsutism, this is more sensitive than total
testosterone for detecting bioavailable androgen excess. It reveals androgen effects
linked to low SHBG; however, its use in men is typically not clinically significant.
ng/dL
nmol/L
g/dL
Free Prostate-Specific Antigen
(PSA) %
Used to distinguish cancer risk from benign prostatic hyperplasia (BPH) when total
PSA is in the "gray zone" (4-10 ng/mL). A low ratio (<10-15%) favors cancer; note
that acute prostatitis or recent ejaculation can cause false positives.
ng/mL
ng/mL
Transtubular Potassium
Gradient
(TTKG)
Determines whether the cause of hypokalemia or hyperkalemia is renal or
extrarenal by
evaluating aldosterone activity in the distal nephron. Reliable only when urine
osmolality is greater than plasma; otherwise, the formula is physiologically
invalid and should not be interpreted.
mmol/L
mmol/L
mOsm/kg
mOsm/kg
mmol/L
Ethanol (Promil/Driving)
Calculator
Converts Serum Ethanol (mg/dL) to Promil (‰).
Legal Note: Legal limit for private drivers in Turkey is
0.50 Promil (50 mg/dL). For commercial drivers, it is 0.20 Promil (20 mg/dL).
mg/dL
‰
Estimated Ionized Calcium
Estimated biologically active calcium level when blood gas devices are
unavailable.
Helpful when total calcium levels do not match symptoms like tetany or
paresthesia;
however, it remains an estimate as it does not account for pH-driven changes in
albumin binding.
mg/dL
g/dL
Ref: 4.4–5.3 mg/dL
Immunoglobulin G (IgG) Index
Evidence of intrathecal immunoglobulin synthesis (inflammation) in the central
nervous system, independent of blood-brain barrier dysfunction. Highly
suggestive of
Multiple Sclerosis, but must be evaluated alongside oligoclonal bands and
clinical
findings for a definitive diagnosis.
mg/dL
g/dL
mg/dL
mg/dL
Transferrin Saturation
A first-line parameter for distinguishing iron deficiency from anemia of chronic
disease and screening for hemochromatosis. Low values indicate iron deficiency,
while high values (>45%) suggest toxic tissue accumulation; note that
inflammation
suppresses transferrin production, potentially causing false high saturation.
µg/dL
µg/dL
Light's Criteria (Pleural
Effusion)
Distinguishes between "transudates" (due to conditions like heart failure) and
"exudates" (resulting from infection or cancer) in pleural effusion cases with
98% sensitivity. In heart failure patients receiving diuretics, fluid may
concentrate and mimic an exudate; in such instances, the serum-pleural albumin
gradient should be assessed.
g/dL
g/dL
U/L
U/L
U/L
Polyethylene Glycol (PEG)
Recovery
Detects Macroprolactinemia, Macroamylasemia, and other macro-enzyme complexes.
Polyethylene Glycol (PEG) precipitates large immune complexes. A recovery < 40%
typically indicates the presence of a macro-complex (e.g., Macroprolactin),
while> 50-60% usually indicates monomeric (true) hormone/enzyme.
conc
conc
Fractional Excretion of Urea
(FEUrea)
Useful when FENa is unreliable due to diuretic use. <35% indicates Prerenal
etiology;>50% suggests Acute Tubular Necrosis (ATN).
Predicts risk of progression to kidney failure requiring
dialysis or transplant (4-variable Tangri equation).
mL/min
mg/g
Hemoglobin
A1c (HbA1c) Converter
Translates the HbA1c percentage used in diabetes monitoring into
an "estimated
average glucose" (eAG) value that patients can more easily
relate to their daily
meter readings. Note that HbA1c (and thus this calculation) can
be misleading in
the presence of hemoglobinopathies or anemia.
%
mmol/mol
AST to Platelet Ratio Index (APRI) Score
Used primarily in Hepatitis C and chronic liver patients to
predict the risk of
fibrosis and cirrhosis without invasive biopsies. While highly
successful at
excluding cirrhosis due to its high negative predictive value,
beware of false
positives during acute hepatitis flares when AST levels
temporarily spike.
U/L
U/L
10³/µL
Winters
Formula (Metabolic Acidosis Compensation)
Monitors whether the body's respiratory response (compensation)
is at the
expected level in patients with metabolic acidosis. If the
measured pCO2 differs
from the calculated value, it indicates a concurrent hidden
respiratory acidosis
or alkalosis (mixed disorder).
Calculates expected pCO2 in primary metabolic acidosis. Compare
with measured
pCO2
to detect
concurrent respiratory disorder.
mEq/L
mmHg
Polyethylene
Glycol (PEG) Recovery
Distinguishes whether unexplained high hormone or enzyme levels
(e.g.,
Prolactin,
Amylase, AST, CK, LDH) are due to true pathological excess or
biologically
inactive "macro-complexes". This avoids misdiagnosis and
unnecessary clinical
interventions; the assessment is based on the recovery rate
following the
Polyethylene Glycol (PEG) precipitation process.
Clinical
References
1. Amylase Studies:
Wyness et al. (2011): They found the % recovery reference
range for the
PEG
method in
healthy individuals to be 38-78%, and for the
ultrafiltration method to
be
86-113%
(median 104). They also showed that these methods could
detect 11 cases
of
macroamylase.
Levitt et al. (1982): In their study on macroamylase
samples, they
determined
a 48%
recovery value as the "cut-off" (threshold) value for
the PEG method.
Lawson (2001): In a large-scale study on 454 individuals,
he compared the
PEG
precipitation method with gel filtration chromatography
and suggested
43% as
the
threshold value.
2. AST
Studies:
Davidson et al. (2013): In a group of 40 people with high
enzyme levels,
they
determined
the % recovery reference range for AST using the PEG
method to be
47-82%.
Wyness et al. (2011): In their study of 125 healthy
individuals, they
found
reference
ranges of 26-88% with the PEG method and 50-89% with the
ultrafiltration
method.
Patteet et al. (2012): In their study on 31 individuals,
they obtained
the
best result
with 25% PEG 6000 concentration and found the reference
range to be
37.5-58%.
Caropreso et al. (2009): They gave the threshold value
for macroAST
detection
in the
pediatric population as 26.7%.
3. Creatine Kinase (CK)
Studies:
Wyness et al. (2011): They determined reference ranges of
36-85% for the
PEG
method and
43-73% for the ultrafiltration method.
Davidson et al. (2013/2012): In one study, they found a
range of 47-82%
for
the PEG
method in a group with high enzyme levels, while in
another study, they
determined the
lower limit as 53% in 255 patients without macroenzymes.
Ciriza and Varo (2015): They recommended 25% PEG 6000 and
10 minutes of
centrifugation as
the optimum method for macroCK detection.
4. LDH
Studies:
Wyness et al. (2011): They determined reference ranges of
18-52% for LDH
with
the PEG
method and 27-63% with ultrafiltration.
Davidson et al. (2013): They found a range of 30-88% with
the PEG method
in
patients with
high enzyme values.
5. Prolactin
Studies:
Ae JC, Schlechte J. Hyperprolactinemia. Pituitary.
11:141–6.
A recovery rate of >60% indicates the presence of
monomeric prolactin,
while
<40% indicates the presence of macroprolactinemia. For
values between 40-60%, clinical correlation is
recommended.
Fractional
Excretion of Urea (FEUrea)
FEUrea is used to distinguish between prerenal azotemia and acute
tubular necrosis
(ATN), particularly in patients taking diuretics where FENa results
may be
unreliable. A value < 35% strongly suggests prerenal causes.
mg/dL
mg/dL
mg/dL
mg/dL
Fractional
Excretion of Calcium (FECa)
FECa helps differentiate Familial Hypocalciuric Hypercalcemia
(FHH) from primary
hyperparathyroidism. A FECa < 0.01 is suggestive of FHH, while>
0.02 suggests
primary hyperparathyroidism.
mg/dL
mg/dL
mg/dL
mg/dL
Amylase-Creatinine Clearance Ratio (ACCR)
Used to differentiate macroamylasemia (clinically insignificant
elevation) from
acute pancreatitis. ACCR > 5% is characteristic of pancreatitis;
values < 1% suggest macroamylasemia.
U/L
U/L
mg/dL
mg/dL
De Ritis
Ratio (AST/ALT)
The ratio of AST to ALT can provide clues to the etiology of
liver disease.
A ratio > 2.0 suggests alcoholic liver disease, while a
ratio < 1.0 is more common in NAFLD or chronic viral
hepatitis.
U/L
U/L
Gamma-Glutamyl Transpeptidase to Platelet Ratio (GPR)
Score
A simple non-invasive marker for cirrhosis and advanced
fibrosis in
patients with chronic Hepatitis B. Calculated as (GGT /
ULN of GGT) /
Platelets.
U/L
U/L
10³/µL
Triglyceride-Glucose (TyG) Index
A reliable surrogate marker for assessing insulin
resistance. It has
shown good correlation with the
hyperinsulinemic-euglycemic clamp
method.
mg/dL
mg/dL
Srivastava Index (MCH/MCV Ratio)
A discrimination index used to differentiate between
iron deficiency
anemia and beta-thalassemia trait based on RBC
parameters.
fL
pg
Soluble Transferrin Receptor (sTfR)-Ferritin Index
Useful for detecting iron deficiency in patients with
concurrent
inflammation, where ferritin alone may be falsely
elevated as an
acute-phase reactant.
mg/L
µg/L
Quantitative Insulin Sensitivity Check Index (QUICKI)
The Quantitative Insulin Sensitivity Check Index
(QUICKI) is a
mathematically derived index using fasting glucose and
insulin levels to
estimate insulin sensitivity.
µIU/mL
mg/dL
Atherogenic Index of Plasma (AIP)
AIP is a strong marker for predicting cardiovascular
disease risk. It reflects the relationship between
protective and
atherogenic lipoproteins (log10 TG/HDL).
mg/dL
mg/dL
Kidney Failure Risk Equation (KFRE)
Estimates the risk of a CKD patient progressing to
kidney failure
requiring dialysis or transplant within 2 and 5 years
(Tangri et al.,
4-variable equation).
mL/min/1.73m²
mg/g
Excel
Decimal Format Tip
Please ensure that uploaded Excel files use a
dot
(.) as
the
decimal
separator. Values containing commas (e.g.,
5,5) may be
skipped.
Excel
Setting: Go
to
File
> Options >
Advanced. Uncheck "Use system
separators"
and set
Decimal
separator to "."
(dot).
Levey-Jennings
Simulator
Levey-Jennings Chart is used to
monitor QC
performance over
time.
Enter data manually or upload via Excel. Use dots
(.) as decimal
separators.
Select Westgard rules to detect out-of-control
conditions.
How to
Use:
Enter Mean and
SD values
(or
select
"Calculate
from data")
Upload QC data via Excel
file or enter
values
manually
Select applicable Westgard
Rules for
violation
detection
Click "CALCULATE & PLOT" to
generate the
L-J chart
Review the chart for rule violations (marked
with different
colors)
10x – Rejection: 10
consecutive points on
same side
of
mean
No
Value
...
PBRTQC (EWMA &
MA)
Patient-Based Real-Time QC (PBRTQC)
uses patient
results to
monitor method
performance.
Upload data via Excel or enter manually. Use dots
(.) as decimal
separators.
Select EWMA or MA method, or use Auto for optimal
parameters.
How to
Use:
Select the Analyte (or
choose Custom for
manual
entry)
Upload patient data via Excel
file or enter
values
manually
Choose EWMA or MA method
(or use Auto)
Adjust truncation and log transformation
options if needed
Click "CALCULATE & PLOT" to
generate the
control
chart
Review for out-of-control signals (points
exceeding control
limits)
Parameter
Abbreviations:
EWMA – Exponentially
Weighted Moving
Average
MA – Moving Average
λ (Lambda) – Smoothing
factor for EWMA (0
to 1)
L – Control limit
multiplier for EWMA
w (Window) – Number of
observations for MA
calculation
RCV – Reference Change
Value for truncation
limits
No
Value
...
Sigma Metric &
Method Decision
Sigma Metric evaluates method
performance using Six
Sigma
methodology.
A Sigma value ≥6 indicates world-class performance,
while ≤3
requires
improvement.
Use Pooled CV for average performance or Separate
for individual QC
levels.
How to
Use:
Select Pooled CV or
Separate
CV
calculation mode
Enter CV% from your QC data
(imprecision)
Enter Bias% from EQA/PT or
method
comparison
Enter TEa (Total Allowable
Error) from
CLIA/EFLM
guidelines
Click "CALCULATE" to
compute Sigma value
Interpret result using Sigma scale (≥6
world-class, <3 poor)
Parameter
Abbreviations:
CV% – Coefficient of
Variation
(imprecision, from
QC
data)
Bias% – Systematic error
(from EQA/PT or
method
comparison)
TEa – Total Allowable Error
(quality
requirement,
from
CLIA/EFLM)
Carryover Analysis detects
sample-to-sample
contamination.
Run samples in the specified sequence (H-L-L-H
pattern) and
enter
results.
If the difference exceeds TEa or 3×SD, carryover
is significant.
How
to
Use:
Enter TEa (Total
Allowable Error) for
the
analyte
Run samples in sequence: H1 → L1
→ L2 → L3 → H2
→ L4 →
L5 →
L6
Enter all measured values in the
respective fields
Click "CALCULATE" to
analyze carryover
Review Group A (L after L) vs Group B (L
after H)
differences
Parameter
Abbreviations:
H – High concentration
sample
L – Low concentration
sample
TEa – Total Allowable
Error (acceptance
limit)
Group A (L after L) –
Low samples
measured
after
other low
samples
Group B (L after H) –
Low samples
measured
after
high samples
Reference Change Value (RCV)
determines if a
change
between
two serial
patient results is clinically significant.
Uses biological variation data to calculate the
expected
variation.
How
to
Use:
Enter Patient's Previous
Result
(baseline
value)
Enter Patient's Current
Result (new
measurement)
Enter CVi, CVg, CVa
values (from
biological
variation database)
Select Z-score for
desired significance
level
Click "CALCULATE" to
compute RCV
Compare % difference with RCV to
determine clinical
significance
Measurement Uncertainty
(MU) quantifies the
range
of
values within
which the true result lies.
This tool uses the Top-Down (Nordtest)
approach optimized
for
clinical
labs using
cumulative QC data.
How
to Use:
Enter CV% from QC
Level 1 and Level
2 data
Enter Bias% from
EQA/PT results
Enter TEa (Total
Allowable Error)
for the
analyte
Optionally check Expanded
Uncertainty for
k=2
factor
Click "CALCULATE"
to compute MU
Verify if U < TEa for
fitness-for-purpose
Parameter
Abbreviations:
CV1, CV2 –
Coefficient of Variation
from QC
Level 1 and
Level 2
u (u_Rw) – Standard
uncertainty
from
reproducibility = CV%
Bias% – Systematic
error from
EQA/PT data
(RMS
Bias)
u_c – Combined
standard uncertainty
= √(u²
+
Bias²)
U – Expanded
uncertainty = k × u_c
(typically
k=2 for 95%
CI)
TEa – Total
Allowable Error for
fitness-for-purpose
evaluation
Data Collection
Guide &
Tips
1.
Data Timeframe
(Crucial):
Values must represent long-term
performance. To capture
variations
(reagent
lots,
maintenance), use cumulative data from
at least
6
months.
2.
Where to find
CV%
(Precision):
Check LIS or Instrument QC Statistics.
Select a 6-month
range,
ensure
"All
Lots" is checked, and use
the
Cumulative
CV.
3.
Where to find
Bias%:
Refer to EQA/PT Reports (e.g., Bio-Rad,
RIQAS). Use the
"RMS
Bias"
or
"Average Bias" from the last 12 months.
Individuality Index (II)
determines whether
population-based
reference intervals are appropriate.
Low II indicates high individuality—serial
monitoring may be
more
useful
than
reference ranges.
How
to Use:
Enter CVi
(within-subject
biological
variation)
Enter CVg
(between-subject
biological
variation)
Click "CALCULATE"
to compute II
Interpret result: II > 1.4 → use
reference
intervals; II < 0.6 → use RCV
Bland-Altman Analysis
assesses
agreement
between
two
measurement methods.
Upload an Excel file with paired
measurements or enter
data
manually.
The plot shows the difference between
methods against
their
mean.
How to Use:
Enter Method
names for labeling
purposes
Upload paired data via
Excel
file or
add
manually
Select Parametric or
Non-Parametric
analysis method
Optionally enter
Allowable
Difference
for
clinical
acceptability
Click "CALCULATE &
PLOT" to
generate
Bland-Altman plot
Review Bias, LoA, proportional
bias, and
clinical
interpretation
Methodology
Guide
1.
Data
Preparation
(Mean &
Difference):
X-Axis
(Mean):
Average
of two
methods:
(A+B)/2. If
one method is
the "gold
standard", you
may use only the
reference value on
X-axis, but
this
can be
misleading.
Y-Axis
(Difference):
Difference
between
measurements:
A−B
2.
Statistical
Parameters:
Mean Difference
(Bias):
Arithmetic
mean of all
differences (d̄). Shows
average
over/underestimation.
Standard
Deviation
(s):
SD of
differences
measures variability.
Limits of
Agreement
(LoA):
Range
containing 95%
of differences:
Bias ± 1.96 × SD
3.
Graph
Components:
Zero
Line:
Horizontal
line at
Y=0
(represents
perfect agreement)
Bias
Line:
Horizontal
line at
mean
difference
(d̄)
LoA
Lines:
Dashed lines
showing
upper and lower
limits
Data
Points:
Each
paired
measurement plotted at
(mean, difference)
4.
Important
Checks:
Normality
Check:
Differences
should
be normally
distributed (use
Shapiro-Wilk test). If
not,
consider log
transformation.
Percentage
Difference:
If
differences increase
with magnitude
(proportional error),
express as
%
difference.
A Priori
Limits:
Clinical
acceptability must be
defined BEFORE
analysis—Bland-Altman
only
describes,
not
decides.
Confidence
Intervals:
Add 95%
CI
for Bias and
LoA to show estimation
precision.
Parameter
Abbreviations:
Bias – Mean
difference between
methods
(systematic
error)
SD – Standard
Deviation of
differences
LoA – Limits of
Agreement (Mean
±
1.96×SD),
contains
95% of differences
95% CI –
Confidence Interval
for Bias
and
LoA
r – Correlation
coefficient for
proportional bias
detection
Important:
If LoA falls within clinically
acceptable
limits,
methods
are
interchangeable.
If Bias CI does not include
zero, systematic
bias is
present.
High correlation (r≈1)
does NOT mean
good
agreement!
Correlation measures linear
relationship, not
agreement.
Clinical acceptability limits
must be defined
a
priori
(before analysis).
Selection Guide: Absolute vs.
Percent
Difference
1. Choose Absolute
Difference
(Units)
if
the
measurement
error remains constant
regardless of the value
(Homoscedasticity).
Best for:
Electrolytes (Sodium,
Calcium),
pH,
or analytes
with
a narrow clinical range.
2. Choose Percent
Difference
(%) if the
measurement
error
increases as the concentration
increases
(Proportional
Bias).
Best for: Enzymes
(ALT, AST, ALP),
Glucose,
Hormones (PSA,
TSH,
HCG), or analytes with very wide
measurement
ranges.
Practical Tip:
Observe the
Trend
Analysis
in results.
If
Proportional Bias is
detected
(correlation r >
0.3), switching
to
Percent Difference (%) often
provides a more
reliable
assessment of
clinical
agreement.
3. X-Axis
Selection: • Mean of Both
Methods:
Standard
for
most cases. It
provides
the best estimate of the true
value when both
methods
have
error.
• Comparative Method
Only:
Use ONLY
if
Method 2 is
a
"Gold Standard" (Reference
Method) with
near-zero error.
Loaded!
No
Method 1
Method 2
Mean
Diff
...
If
LoA
exceeds this
limit,
methods
are not interchangeable
Tip: Use
Percent
Difference when
comparing methods
across a wide measurement range to
detect
proportional bias.
Parametric: For
normally
distributed
differences
|
Non-Parametric:
When normality is
not met
Correlation
Plot
(Method 1 vs
Method 2)
Laboratory Handbook
Turkish Ministry of Health, Medical Biochemistry
Regulations,
Letters,
Legislation
Documents.
(Primarily for Turkish users)
Mayo Clinic Labs
Test
Catalog
Clinical Lab
Diagnostics
Online
Textbook
ADLM (AACC)
Lab
Medicine
Authority
Lab Tests Online
Test
Explanations
Harmonization
Database
International
Measurands
TBD
Türk
Biyokimya
Derneği
TKBD
Türk
Klinik
Biyokimya
Uzmanları
Derneği
KBUD
Klinik
Biyokimya
Uzmanları
Derneği
Reddit MedLab
Global
Lab
Community
Lab Error Finder
Lab
Error
Finder
QC Constellation
Quality
Control
App
CALIPER
Pediatric
Reference
Intervals
Journals
Please
select
the
journals
you
wish to
follow and the number of recent articles
to display,
then click
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to
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