Lab Work Cost in Chattanooga, TN
Lab work involves collecting a blood sample, usually from a vein in the arm, and sending it to a hospital laboratory where instruments analyze it and produce numerical results that a clinician reviews. The hospital facility fee covers the laboratory's equipment, supplies, and staff time to run the analysis, but not a physician's interpretation. This page covers two billing codes: 80053 Comprehensive Metabolic Panel (CMP) and 85025 Complete Blood Count (CBC) with Differential. All prices come from the price transparency files that CMS requires US hospitals to publish, and they reflect facility charges at four Chattanooga area hospitals.
Data last accessed by us: 2026-10-15 · Newest hospital file date among hospitals below: 2026-09-01
Data may be outdated
This hospital's pricing file has not been updated since 2026-01-25 (263 days ago). Prices may not reflect current charges. Contact the hospital directly for current pricing.
Comprehensive Metabolic Panel (CMP) (HCPCS 80053)
Hide Show
| Hospital | Cash Price | |
|---|---|---|
| CHI Memorial Chattanooga | $261.84 | Schedule → |
| CHI Memorial Hixson | $183.23 | Schedule → |
| Parkridge East * | $1,413.59 * | Schedule → |
| Parkridge Medical Center * | $1,413.59 * | Schedule → |
Complete Blood Count (CBC) with Differential (HCPCS 85025)
Hide Show
| Hospital | Cash Price | |
|---|---|---|
| CHI Memorial Chattanooga | $118.44 | Schedule → |
| CHI Memorial Hixson | $82.88 | Schedule → |
| Parkridge East * | N/A * | Schedule → |
| Parkridge Medical Center * | N/A * | Schedule → |
What These Prices Mean
The gross charge is a hospital's list price before any discounts. The cash price is what a self-pay patient is quoted, and the insured range spans the lowest to highest rates negotiated with health plans. At CHI Memorial Hospital Chattanooga, the CMP has a gross charge of $619, a cash price of $261.84 (42% of gross), and an insured range of $9.38 to $433.30. At CHI Memorial Hospital Hixson, the same code lists a cash price of $183.23, or 30% of gross. At Parkridge East Hospital and Parkridge Medical Center, the CMP cash price of $1,413.59 equals the gross charge, so no self-pay discount is published. People on a high-deductible plan who have not yet met their deductible usually pay the plan's negotiated rate, not the gross charge.
CMP versus CBC pricing
The CMP (80053) carries higher listed amounts than the CBC with differential (85025) at the hospitals that publish both. CHI Memorial Hospital Chattanooga lists a $619 gross charge for the CMP and $280 for the CBC. Its insured range tops out at $433.30 for the CMP and $196 for the CBC. At both Parkridge hospitals, the CBC has no published gross charge or cash price, so those fields are missing data, while its insured rates run from $3.50 to $43.75.
Why Lab Work Prices Vary
The four hospitals belong to two systems, CHI Memorial (CommonSpirit) and HCA Parkridge, and their published policies differ. Both CHI Memorial hospitals list the same gross charges, $619 for the CMP and $280 for the CBC, yet their cash prices differ: $183.23 and $82.88 at Hixson (30% of gross) versus $261.84 and $118.44 at Chattanooga (42% of gross). Excluding the two hospitals whose cash equals gross, cash prices run from $82.88 to $261.84, and the highest is about 3x the lowest. Gross charges run from $280 to $1,413.59, about 5x from lowest to highest. Parkridge East Hospital and Parkridge Medical Center publish cash equal to gross.
Beyond this dataset and across plans
Outpatient centers, independent laboratories, and other facilities are not part of this dataset and may price the same tests differently. Insurer data shows wide variation too. For the CMP at Parkridge Medical Center, the payer table lists 231 published rates, from $4.75 (Wellpoint) to $1,243.96 (Beech Street and Prime Health), and the highest is about 262x the lowest. The same plan names can also appear with different networks.
Paying cash? Health insurance could lower your Lab Work cost.
Published cash prices on this page range from $82.88 to $1,413.59 (including hospitals that publish cash equal to gross charge, marked with * in the table). The lowest insured rate in the price table is $3.50 (Parkridge East Hospital). Insured rates depend on the plan, and the lowest are often Medicaid, CHIP or Medicare Advantage plans, so they may not reflect what a commercial or marketplace plan pays. If you are uninsured, a marketplace health plan could reduce your out-of-pocket cost for this procedure.
Links go to Healthcare.gov, the official federal health insurance marketplace. We are not affiliated with Healthcare.gov or any insurance provider. This is not a recommendation for any specific plan.
Compare Insurer Rates for Lab Work in Chattanooga
How much does each insurance company pay for lab work at Chattanooga hospitals?
| Insurer | Lowest Rate | Hospitals |
|---|---|---|
| UnitedHealthcare | $10.56 | 4 |
| Amerigroup | $10.56 | 4 |
| Humana | $10.56 | 4 |
| BlueCross BlueShield of Tennessee | $10.61 | 4 |
| Aetna | $10.67 | 4 |
| Cigna | $11.09 | 4 |
Rates shown are the lowest and highest negotiated rates each insurer has published across Chattanooga hospitals for this procedure. Your actual cost depends on your plan's deductible, copay, and coinsurance.
What Insurers Actually Pay
Hide Show
Published negotiated rates for Comprehensive Metabolic Panel (CMP) (HCPCS 80053) at Parkridge Medical Center, outpatient facility fee:
Comprehensive Metabolic Panel (CMP) (80053), Parkridge Medical Center Payer Rates
| Insurance Payer | Plan Type | Negotiated Rate |
|---|---|---|
| Wellpoint | MGMCD | $4.75 |
| BCBS | NetworkS | $8.23 |
| BCBS | NetworkS | $8.23 |
| BCBS | NetworkS | $8.23 |
| BCBS | NetworkS | $8.23 |
| BCBS | NetworkS | $8.23 |
| BCBS | NetworkS | $8.23 |
| BCBS | NetworkS | $8.23 |
| BCBS | NetworkS | $8.23 |
| Aetna | COMM | $8.96 |
| Aetna | NewBusiness | $8.96 |
| United | AllPayerAppendix | $10.56 |
| United | Core | $10.56 |
| United | HeritageSelect | $10.56 |
| United | AllPayerAppendix | $10.56 |
| United | Core | $10.56 |
| United | HeritageSelect | $10.56 |
| United | AllPayerAppendix | $10.56 |
| United | Core | $10.56 |
| United | HeritageSelect | $10.56 |
| United | AllPayerAppendix | $10.56 |
| United | Core | $10.56 |
| United | HeritageSelect | $10.56 |
| United | AllPayerAppendix | $10.56 |
| United | Core | $10.56 |
| United | HeritageSelect | $10.56 |
| United | AllPayerAppendix | $10.56 |
| United | Core | $10.56 |
| United | HeritageSelect | $10.56 |
| United | AllPayerAppendix | $10.56 |
| United | Core | $10.56 |
| United | HeritageSelect | $10.56 |
| United | AllPayerAppendix | $10.56 |
| United | Core | $10.56 |
| United | HeritageSelect | $10.56 |
| United | AllPayerAppendix | $10.56 |
| United | Core | $10.56 |
| United | HeritageSelect | $10.56 |
| Amerigroup | MGMCR | $10.56 |
| Bright Health | HIX | $10.56 |
| Bright Health | SmallGroup | $10.56 |
| Devoted Health Plan | MCR | $10.56 |
| Healthspring | DualEligible | $10.56 |
| Healthspring | MCRHMO | $10.56 |
| Healthspring | MCRPOS | $10.56 |
| Healthspring | MCRPPO | $10.56 |
| Hearth Hospice | COMM | $10.56 |
| Humana | ChoicecareMGMCR | $10.56 |
| Sarah Cannon Research | COMM | $10.56 |
| United | VACCN | $10.56 |
| United Behavioral Health | VACNN | $10.56 |
| United | AllPayerAppendix | $10.56 |
| United | Core | $10.56 |
| United | HeritageSelect | $10.56 |
| United | AllPayerAppendix | $10.56 |
| United | Core | $10.56 |
| United | HeritageSelect | $10.56 |
| Aetna | MGMCRHMO | $10.67 |
| Aetna | MGMCRPPO | $10.67 |
| Aetna | MGMCRSNP | $10.67 |
| BCBS | MCR | $10.77 |
| United | MGMCR | $10.77 |
| WellCare | MCR | $10.88 |
| Zing | MGMCR | $10.88 |
| Aetna Better Health of Georgia | MCD | $11.09 |
| American Health Advantage | MCRHMO | $11.09 |
| American Health Advantage | MCRPFFS | $11.09 |
| American Health Advantage | MCRPOS | $11.09 |
| American Health Advantage | MCRPPO | $11.09 |
| American Health Advantage | MCRSNP | $11.09 |
| Clover Insurance | MCR | $11.09 |
| Evergreen HMO | MCR | $11.09 |
| Signature Advantage | MCR | $11.19 |
| ATRIO Golden Times | MCR | $11.62 |
| BCBS | NetworkP | $11.76 |
| Bright Health | MCRNarrow | $12.14 |
| Health One Alliance | COMMHIX | $12.67 |
| BCBS | TENNCARE | $14.78 |
| Prime Health | WORKERSCOMP | $15.21 |
| CorVel Corporation | WORKERSCOMP | $15.52 |
| NovaNET | WORKERSCOMP | $15.52 |
| BCBS | COVERKIDS | $16.10 |
| Cigna | NewBusiness | $17.78 |
| Peach State (Ambetter) | HIX | $19.01 |
| Peach State (Ambetter) | HIX | $19.01 |
| Peach State (Ambetter) | HIX | $19.01 |
| Peach State (Ambetter) | HIX | $19.01 |
| Peach State (Ambetter) | HIX | $19.01 |
| Peach State (Ambetter) | HIX | $19.01 |
| Peach State (Ambetter) | HIX | $19.01 |
| Peach State (Ambetter) | HIX | $19.01 |
| Peach State (Ambetter) | HIX | $19.01 |
| Peach State (Ambetter) | HIX | $19.01 |
| Peach State (Ambetter) | HIX | $19.01 |
| Peach State (Ambetter) | HIX | $19.01 |
| Peach State (Ambetter) | HIX | $19.01 |
| Peach State (Ambetter) | HIX | $19.01 |
| Peach State (Ambetter) | HIX | $19.01 |
| Peach State (Ambetter) | HIX | $19.01 |
| Peach State (Ambetter) | HIX | $19.01 |
| Peach State (Ambetter) | HIX | $19.01 |
| Peach State (Ambetter) | HIX | $19.01 |
| Peach State (Ambetter) | HIX | $19.01 |
| Peach State (Ambetter) | HIX | $19.01 |
| Peach State (Ambetter) | HIX | $19.01 |
| Peach State (Ambetter) | HIX | $19.01 |
| Peach State (Ambetter) | HIX | $19.01 |
| Peach State (Ambetter) | HIX | $19.01 |
| Peach State (Ambetter) | HIX | $19.01 |
| Peach State (Ambetter) | HIX | $19.01 |
| Peach State (Ambetter) | HIX | $19.01 |
| Peach State (Ambetter) | HIX | $19.01 |
| Peach State (Ambetter) | HIX | $19.01 |
| Peach State (Ambetter) | HIX | $19.01 |
| Peach State (Ambetter) | HIX | $19.01 |
| Peach State (Ambetter) | HIX | $19.01 |
| Peach State (Ambetter) | HIX | $19.01 |
| Peach State (Ambetter) | HIX | $19.01 |
| Peach State (Ambetter) | HIX | $19.01 |
| Peach State (Ambetter) | HIX | $19.01 |
| Peach State (Ambetter) | HIX | $19.01 |
| Peach State (Ambetter) | HIX | $19.01 |
| Peach State (Ambetter) | HIX | $19.01 |
| Peach State (Ambetter) | HIX | $19.01 |
| Peach State (Ambetter) | HIX | $19.01 |
| Peach State (Ambetter) | HIX | $19.01 |
| Peach State (Ambetter) | HIX | $19.01 |
| Peach State (Ambetter) | HIX | $19.01 |
| Peach State (Ambetter) | HIX | $19.01 |
| Peach State (Ambetter) | HIX | $19.01 |
| Peach State (Ambetter) | HIX | $19.01 |
| Peach State (Ambetter) | HIX | $19.01 |
| Peach State (Ambetter) | HIX | $19.01 |
| Peach State (Ambetter) | HIX | $19.01 |
| Peach State (Ambetter) | HIX | $19.01 |
| Peach State (Ambetter) | HIX | $19.01 |
| Peach State (Ambetter) | HIX | $19.01 |
| Peach State (Ambetter) | HIX | $19.01 |
| Peach State (Ambetter) | HIX | $19.01 |
| Peach State (Ambetter) | HIX | $19.01 |
| Ambetter | CORE | $19.54 |
| Ambetter | CORE | $19.54 |
| Cigna | OAP | $22.08 |
| BCBS | BlueCare | $31.65 |
| Amerigroup | MCD | $214.87 |
| Amerigroup | MCD | $214.87 |
| Amerigroup | MCD | $214.87 |
| BCBS | NetworkS | $254.45 |
| BCBS | NetworkS | $254.45 |
| BCBS | NetworkS | $254.45 |
| Kentucky Labor Cabinet | WORKERSCOMP | $260.24 |
| Kentucky Labor Cabinet | WORKERSCOMP | $260.24 |
| Kentucky Labor Cabinet | WORKERSCOMP | $260.24 |
| Apex Health | MCR | $268.58 |
| NHC Advantage, Inc. | MCRHMO | $268.58 |
| Pruitt Health (AllyAlign) | MCR | $268.58 |
| Apex Health | MCR | $268.58 |
| NHC Advantage, Inc. | MCRHMO | $268.58 |
| Pruitt Health (AllyAlign) | MCR | $268.58 |
| Apex Health | MCR | $268.58 |
| NHC Advantage, Inc. | MCRHMO | $268.58 |
| Pruitt Health (AllyAlign) | MCR | $268.58 |
| Peach State | MGMCD | $282.72 |
| Wellcare | MCD | $282.72 |
| Peach State | MGMCD | $282.72 |
| Wellcare | MCD | $282.72 |
| Peach State | MGMCD | $282.72 |
| Wellcare | MCD | $282.72 |
| Humana | TRICARE | $353.40 |
| Humana | TRICARE | $353.40 |
| Humana | TRICARE | $353.40 |
| BCBS | StandardBH | $438.21 |
| BCBS | StandardBH | $438.21 |
| BCBS | StandardBH | $438.21 |
| United | OptionsPPO | $470.73 |
| United | OptionsPPO | $470.73 |
| United | OptionsPPO | $470.73 |
| Cigna | PPO | $484.86 |
| Cigna | PPO | $484.86 |
| Cigna | PPO | $484.86 |
| United | GlobalBenefitPlan | $636.12 |
| United | GlobalBenefitPlan | $636.12 |
| United | GlobalBenefitPlan | $636.12 |
| Aetna | NAP | $706.79 |
| Value Option | COMM | $706.79 |
| Aetna | NAP | $706.79 |
| Value Option | COMM | $706.79 |
| Aetna | NAP | $706.79 |
| Value Option | COMM | $706.79 |
| Magellan Behavioral Health | COMM | $848.15 |
| Magellan Behavioral Health | MCR | $848.15 |
| Multiplan | COMM | $848.15 |
| Magellan Behavioral Health | COMM | $848.15 |
| Magellan Behavioral Health | MCR | $848.15 |
| Multiplan | COMM | $848.15 |
| Magellan Behavioral Health | COMM | $848.15 |
| Magellan Behavioral Health | MCR | $848.15 |
| Multiplan | COMM | $848.15 |
| Health One Alliance | PPO | $918.83 |
| Humana BH | MCR | $918.83 |
| North GA Health Services | COMMPPO | $918.83 |
| Health One Alliance | PPO | $918.83 |
| Humana BH | MCR | $918.83 |
| North GA Health Services | COMMPPO | $918.83 |
| Health One Alliance | PPO | $918.83 |
| Humana BH | MCR | $918.83 |
| North GA Health Services | COMMPPO | $918.83 |
| Health One Alliance | HMOPOS | $961.24 |
| Health One Alliance | HMOPOS | $961.24 |
| Health One Alliance | HMOPOS | $961.24 |
| Employers Health Network | COMM | $989.51 |
| Olympus Managed Healthcare | COMMPPO | $989.51 |
| Employers Health Network | COMM | $989.51 |
| Olympus Managed Healthcare | COMMPPO | $989.51 |
| Employers Health Network | COMM | $989.51 |
| Olympus Managed Healthcare | COMMPPO | $989.51 |
| MHNet | COMM | $1,060.19 |
| MHNet | COMM | $1,060.19 |
| MHNet | COMM | $1,060.19 |
| Cigna Evernorth Behavioral Health | COMM | $1,130.87 |
| ComPsych | COMM | $1,130.87 |
| Cigna Evernorth Behavioral Health | COMM | $1,130.87 |
| ComPsych | COMM | $1,130.87 |
| Cigna Evernorth Behavioral Health | COMM | $1,130.87 |
| ComPsych | COMM | $1,130.87 |
| Beech Street | COMM | $1,243.96 |
| Prime Health | COMMPPO | $1,243.96 |
| Beech Street | COMM | $1,243.96 |
| Prime Health | COMMPPO | $1,243.96 |
| Beech Street | COMM | $1,243.96 |
| Prime Health | COMMPPO | $1,243.96 |
Key finding: For the CMP at Parkridge Medical Center, published insurer rates run from $4.75 (Wellpoint) to $1,243.96 (Beech Street and Prime Health), about 262x apart, across 231 listed rates.
What to Do With These Lab Work Prices
Pin down the test list before you call. Prices here are per test code, so ask the ordering office exactly which codes are on the requisition. This page covers 80053 (CMP) and 85025 (CBC with differential). Then ask the hospital lab for its cash or self-pay price and an itemized estimate that lists each code separately, plus the specimen collection (venipuncture) charge, since one blood draw can carry several codes and a collection fee.
Hold the quote up to the numbers above. At CHI Memorial Hospital Hixson, the CMP cash price is $183.23, while the insured range for that code runs up to $433.30. At Parkridge East Hospital, the CMP cash price is $1,413.59, which sits above the highest insured rate of $1,243.96 at the same hospital. If a quote or bill lands far outside these figures, you can ask the billing office to explain the difference.
Read the bill line by line.
- Check how many tests were billed and whether the same panel appears twice.
- Look for a separate specimen collection line.
- Check whether a facility charge and a separate professional fee (such as a pathologist's reading) are both listed, and whether any of it arrives as a second bill from another provider.
Missing data and missing labs. For the CBC at Parkridge East Hospital and Parkridge Medical Center, the gross charge and cash price are published as $0 or blank. That means the data is missing, not that the test is free. Also, independent labs are not part of this dataset, and they can price the same test very differently from a hospital outpatient lab, so ask the ordering office where the sample will be processed.
Financial assistance and discounts. Nonprofit hospitals are required to publish a financial assistance policy, and the billing office can send it with an application. Some hospitals also offer prompt-pay or self-pay discounts; these vary by hospital and are not included in this data. If you are uninsured or not using insurance for scheduled care, you can ask the provider for a good faith estimate before the appointment.
General information about using published prices, not medical, legal or financial advice. Confirm your own cost with the hospital and your insurer. Our methodology · Medical Disclaimer
What Patients Ask About Lab Work Costs
How much does a lab work cost without insurance in Chattanooga?
Published cash prices for lab work in Chattanooga range from $82.88 at CHI Memorial Hospital Hixson (CBC with differential) to $1,413.59 at Parkridge East Hospital (CMP). Parkridge Medical Center also lists $1,413.59 for the CMP, equal to its gross charge. Cash prices for the CBC are not published at Parkridge East Hospital or Parkridge Medical Center, so that is missing data and not a real price. CHI Memorial Hospital Chattanooga lists $261.84 for the CMP and $118.44 for the CBC. These are facility charges only. Professional fees, such as a physician's review of results, are billed separately.
Why is the gross charge so much higher than the cash price?
The gross charge is a hospital's full list price, which few patients actually pay. Cash prices are often a discounted amount. At CHI Memorial Hospital Chattanooga, cash is 42% of gross for both codes, and at CHI Memorial Hospital Hixson it is 30%. Parkridge East Hospital and Parkridge Medical Center publish a cash price for the CMP equal to the $1,413.59 gross charge, which is 100%, so no self-pay discount appears in their files. The gap between gross and cash therefore depends on each hospital's own discount policy.
Does insurance cover a lab work?
Whether insurance applies to lab work depends on your specific plan, so the plan's own documents or the insurer are the sources for coverage details. The hospital files list negotiated rates by insurer. For the CMP, insured rates run from $4.75 to $1,243.96 at the Parkridge hospitals and from $9.38 to $433.30 at the CHI Memorial hospitals. For the CBC, they run from $3.50 to $43.75 at the Parkridge hospitals and from $6.91 to $196 at CHI Memorial. If you are on a high-deductible plan and have not met your deductible, you usually pay the plan's negotiated rate until it is met.
Are there additional fees beyond the lab work facility charge?
The facility charge for lab work typically covers only the laboratory's analysis. Other bills can arrive separately. A physician or pathologist may bill a professional fee for reviewing or interpreting results. A clinic, emergency department, or hospital outpatient visit may add its own facility or visit charge if the blood draw happens as part of a larger encounter. Specimen collection, handling, or additional tests ordered alongside the panel may also be billed as separate line items. An itemized bill from the hospital lists each charge individually.
What is the cash price for a comprehensive metabolic panel at CHI Memorial Hospital Chattanooga?
CHI Memorial Hospital Chattanooga lists a cash price of $261.84 for the comprehensive metabolic panel (80053), against a gross charge of $619. That cash figure is 42% of the gross charge. These are facility charges only and do not include separate professional or physician fees.
What is the lowest cash price for lab work in Chattanooga?
The lowest published cash price on this page is $82.88 for the complete blood count with differential (85025) at CHI Memorial Hospital Hixson. It is a facility charge only. The gross charge listed for that code is $280, and the cash price is 30% of it.
Do Parkridge East Hospital and Parkridge Medical Center publish a self-pay discount for lab work?
No discount appears in the data. Both list a cash price of $1,413.59 for the comprehensive metabolic panel (80053), equal to the gross charge. For the complete blood count (85025), the gross charge and cash price are blank or $0, which means missing data, not free. All figures are facility charges only.
What are the insured rates for a CBC with differential (85025) at Chattanooga hospitals?
Insured rates for 85025 on this page run from $3.50 to $43.75 at Parkridge East Hospital and Parkridge Medical Center. At both CHI Memorial hospitals, Chattanooga and Hixson, they run from $6.91 to $196. All four hospitals have at least one insured rate listed. These are facility charges only.
Why is the cash price for a metabolic panel at Parkridge Medical Center higher than some insured rates?
For the comprehensive metabolic panel (80053), Parkridge Medical Center lists a cash price of $1,413.59, while its insured rates run from $4.75 to $1,243.96. The cash figure equals the gross charge, with no self-pay discount published. The payer table lists 231 rates for this code. All figures are facility charges only.
Compare Other Procedures in Chattanooga
Data Sources
Hide Show
Heads up: source files are large
Hospital CMS transparency files typically range from tens of megabytes to several hundred megabytes. Clicking a link below will open the file in a new tab and may trigger a large download, which can consume mobile data or slow down older devices. These files are intended for data processing, not casual viewing.
CHI Memorial Hospital Chattanooga
File updated: 2026-02-28 · Accessed by us: 2026-10-15
Attested by: Janelle Reilly , Market President, SE Tennessee/N Georgia
We are not affiliated with CHI Memorial Hospital Chattanooga. Published prices may not reflect your actual cost. Disclaimer
⚠ Large file, opens in new tab
CHI Memorial Hospital Hixson
File updated: 2026-02-28 · Accessed by us: 2026-10-15
Attested by: Janelle Reilly , Market President, SE Tennessee/N Georgia
We are not affiliated with CHI Memorial Hospital Hixson. Published prices may not reflect your actual cost. Disclaimer
⚠ Large file, opens in new tab
Erlanger Baroness Hospital
File updated: 2026-01-25 · Accessed by us: 2026-10-15
Attested by: Lynn S. DeJaco
We are not affiliated with Erlanger Baroness Hospital. Published prices may not reflect your actual cost. Disclaimer
⚠ Large file, opens in new tab
Parkridge East Hospital
File updated: 2026-09-01 · Accessed by us: 2026-10-15
Attested by: Nicholas Pounder
We are not affiliated with Parkridge East Hospital. Published prices may not reflect your actual cost. Disclaimer
⚠ Large file, opens in new tab
Parkridge Medical Center
File updated: 2026-09-01 · Accessed by us: 2026-10-15
Attested by: Christopher Cosby
We are not affiliated with Parkridge Medical Center. Published prices may not reflect your actual cost. Disclaimer
⚠ Large file, opens in new tab